Winter Layup - 1995 Ducati 900 Supersport

[Ocean1]

Much better. Maybe a touch hot looking at that undercut, but you're on the way.

Ah, and those wee pinholes are at the end of a run? Set up your current down ramp to 4-5 sec and gas post-flow to about 10 sec and leave the dying arc on the work until it stops.

[OddDuck]

The first frame weld actually went OK. This was a simple re-melt of a weld bead, right hand top frame rail, first vertical upright. I'd seen what looked like a couple of fine cracks and wanted to be sure.

The second - repairing the very obvious crack at the root of the reinforcing gusset - didn't go well at all. Getting into a frame turned out to be quite a step up from welding dinky little sample pieces on a table. Lots of foulups, lots of distractions... at this point I should have taken a break but I had the blood up. After about five goes at it on the folding table, I finally realised that I couldn't see a thing through the mask, and this was because I had the garage door open. Sunlight was causing problems with the mask.

In the meantime I'd managed to blow a hole through the frame... shit, shit, shit. I filled it with rod toot sweet, then engaged brain (finally) and realised what the problem was. Guess what, just because one visible piece of tubing is 2.4mm wall thickness, it doesn't mean the whole thing is.

Crystal clear in hindsight. Presumably welders with more skill simply make test puddles and set amperage by that.

Afterthoughts: the X-ray technique I'd played with earlier could have told me this. If I put some samples of commercial tube next to the frame, then took a shot and compared signal count through frame vs sample, I could have a non-destructive measurement of wall thickness that way. Another way - find a wrecked frame and hacksaw the thing, then get the calipers out.

Anyway... it looks like the tubing is 1.6mm wall thickness, or thereabouts. I finally lost patience with abortive attempts to weld on the table and rejigged the frame as shown, with the weld zone flat on the workbench and relatively accessible.

Weld's pictured. It's not the best really but anything more I do to it is just going to make it worse.

[OddDuck]

Much better. Maybe a touch hot looking at that undercut, but you're on the way.

Ah, and those wee pinholes are at the end of a run? Set up your current down ramp to 4-5 sec and gas post-flow to about 10 sec and leave the dying arc on the work until it stops.

Ta. Yeah, the undercut on the flank has happened a couple of times - I'm starting to think that I should file the notched tube back until it's a proportion of original thickness, say 50%? At the very edge it's paper thin. The other thing is that maybe in the neck I should turn current up a bit, since in direction of weld, the material's a lot thicker.

I've already got current down ramp and post flow, but will have to check times - probably shorter than you recommend. I know I've got to learn patience and keep the torch in place, welding rod too, during the post weld phase.

[Ocean1]

Ta. Yeah, the undercut on the flank has happened a couple of times - I'm starting to think that I should file the notched tube back until it's a proportion of original thickness, say 50%? At the very edge it's paper thin. The other thing is that maybe in the neck I should turn current up a bit, since in direction of weld, the material's a lot thicker.

I've already got current down ramp and post flow, but will have to check times - probably shorter than you recommend. I know I've got to learn patience and keep the torch in place, welding rod too, during the post weld phase.

The undercut is partly torch angle and partly not enough filler. Filler rod is a heat sink, the process is basically make a puddle forward from the last deposit and centered on the joint, then dab the rod to fill the puddle and move forward again. If the torch angle isn't centered you tend to end up pulling parent material from the hot side into the puddle. You need to keep the rod just out of the arc, too where it takes just a prod to add filler, too far away and it gets out of the gas shield and all crusty. The main trick is to develop that cycle rhythm so you end up with even deposits looking like stacked coins or fish scales.

It's frustrating, you look at tredley bike frames and the welds are perfect, but they're done by either a guy that's done that particular joint a thousand times or a robot. And to be honest most motorcycle frame welds aren't flash. Yours frame was mig welded too, originally, which is a production process and never looks as good.

[actungbaby]

[QUOTE=OddDuck;1130994658]The first frame weld actually went OK. This was a simple re-melt of a weld bead, right hand top frame rail, first vertical upright. I'd seen what looked like a couple of fine cracks and wanted to be sure.

I think your doing great i chould not do this . just feel you chould make alot better if you had frame held firm and not so far into a bench

means your already having to be bent over thinking about you body posture and having relaxed arms .just a thought to try help you.

Weld looks okay its the strength your looking for i mean it looking a certain way i guessing shows flow .

am sure your inspiring many people to give things a go . dont beat yourself up frame welding must be one most demanding skills

[OddDuck]

The MBP retainers and the EMS shims arrived earlier this week - turnaround was about a week, very prompt - so the last few nights have been about re-shimming valve clearances.

I'm very impressed with the MBP retainers. There has been some comment about them being a tight fit in OEM Ducati closing shims but they fit straight into the EMS ones. The EMS measuring tool for opening shims is also very good.

Closing shims are fussy bastards to fit for the first time. Lacking a shim kit (would have made life a lot easier) I ended up very carefully sanding these down, fitting, trying for play. Unfortunately it was a lot of work. Ducati recommend a 0.000" to 0.00079" clearance for all openers... there isn't much margin for sanding too far. If I'd bought the shim kit, I'd have found the closest loose size, measured the clearance, and then known what to sand the next biggest shim size down to. That could have been done on the bench with verniers and the EMS measuring tool, would have been a lot faster.

As it was, I found that the best way to test for fit wasn't to use feeler gauges but instead to fit and try turning the camshaft. If it was too tight then I could feel it very clearly, also I could feel the tightness easing off as I sanded it down until I finally had the right size.

Once that was done, opening shims were fitted, rocker arms slid across and retaining clips fitted. Something about these clips affects the opening shim clearances. There can be a difference of 0.003" or more if you take these off and then measure.

Lot of sanding, again. Nearly managed to order these right, in the end I had to take 0.10 mm off all of them in order to get the right running clearance.

I went around all valves with the feeler gauges when everything was done. Both opening and closing clearances are taken in the same place, between the opening rocker arm and the opening shim. First take the opening clearance, using the feeler gauge. Then push down on the closing rocker arm with a screwdriver, so you push against the spring and take up any slack, then measure with the feeler gauge again. Any increase is the closing arm clearance.

[pete376403]

Are the shims hardened right through or case hardened? In other words is there a risk of sanding/grinding off the hardening? I guess if valve clearances change very rapidly after running then they are not through hardened.

[OddDuck]

Are the shims hardened right through or case hardened? In other words is there a risk of sanding/grinding off the hardening? I guess if valve clearances change very rapidly after running then they are not through hardened.

They're through hardened - check this page:

http://emsduc.com/wp-content/uploads/2015/06/General_Shim_and_Shim_Kit_Information-052915.pdf

Shouldn't be a problem. I have to admit that I'm concerned about the valves themselves bedding in a bit and clearances changing, I'll run the motor for a week or so and check clearances again.

[OddDuck]

Valve guide seals.

I've been trying a few things with the three types of aftermarket seals I'd ordered, trying to make them fit. The black seals pictured were initially very promising but I found three problems:

- they go oval with the spring clip fitted;
- they pull off easily;
- they just (only just) interfere with the closing rocker arm. I could see the rubber seal flex by using a mechanic's mirror.

Damn.

I tried another kind, part no. 761.389 (green, made by Elring, sourced from Mick's Garage) and found that it would actually work provided that I block-and-papered the metal outer ring down to a width of 5.0 mm. The cut-down M12 washer was used as a tool to help push the modified seal over the valve stem guide. I greased everything before pushing it on, it's possible to feel it pop into place. Once on, it needed screwdrivers to lever it off. I didn't have to modify the valve guide.

This worked very well on the exhaust valve guides but wouldn't fit on the inlet guides - these sit taller and there are interference problems with the closer arm. I've fitted the OEM Ducati seals (for now), these go on by using a small Allen key and stretching them over the guide boss.

They fit, obviously they work, but I have serious doubts about these over the long run. There's nothing backing the rubber up. Once they stretch or set, either at the valve stem or the guide boss, there'll be plenty of oil hitting that guide. Too much oil attracts carbon, which then grinds the valve stem and guide.

[OddDuck]

Finally, onto the frame top front triangle.

I cleaned the insert tube up and tacked in four points, then started to do the perimeters. This is a very slow process of turning the frame on the bench, trying for access and motion with the torch and filler rod, checking that the torch cable doesn't snag halfway through the pass, being sure before attempting to spark up.

I've bought a zero length back cap to help the torch navigate tight corners. Using this is easy: snap tungstens in half, resharpen and you're good to go.

Any tubing which has been bent will have thinned out through its wall on the positive side of the curve. Very easy to blow holes into, unfortunately. I should have trimmed the top wings of the fishmouths back a bit to avoid this - welding to the neutral axis of the bend and no further would have been a lot less tricky.

The first welds (about 2 / 5 ths of the perimeter covered so far) shown. The problems I'm encountering are difficulty getting the mask close enough to clearly see the weld zone and the rapid changes in weld current required progressing around the curve. Doing this is very different to welding up short little samples on the table - I had full hemispherical access with those and I could get the mask close. Doing this is making me really appreciate the skill level a professional frame repairer brings to the job.

[OddDuck]

I spent the week trying to complete welding the frame tube into place.

It's been an absolute bastard of a job. Lots of difficulty with either seeing the weld zone, handling the torch, or getting filler rod in. Or all three... TIG's really best with hemispherical access above the weld. I ended up purchasing a foot control last night and trying it this morning, would have helped earlier but didn't really achieve much today while trying to work in the most difficult part of the weld.

MIG would have been good, I think... it's possible to direct filler rod straight into a narrow gap. I think it might also be relatively easy to put a decent bead in without blowing holes in the thin frame tubes, but I'd have to try it for myself.

Very tired, have had enough of welding for now.

[OddDuck]

After a lot of thinking, I have decided to run with the welds as they are.

I've been painting. Went to a local body shop, left the frame with them, had them colour match and fill up some spray cans. I got some primer in the same paint system while I was at it. The lower front cross bar was starting to rust, so I took the chance to sand it back to bare metal and start on the paint again.

There's a slight colour mismatch between front (new paint) and rear halves of the frame. I could overcoat the whole thing (after properly washing the rear half), but it'd be good to keep the original colour. It's still possible to put another coat or two on without any problems, does anyone know the paint codes for the Ducati metallic silver used on the frame?

[pete376403]

Silver must be one of the hardest colours to match, even having the correct paint codes isn't going to help much when the original paint has 20 years of weathering.

[OddDuck]

Thanks Pete - those are words of wisdom, repaint the entire frame it is.

With that in mind I had a good long look at the custom mixed paint tonight... and I can't stand the stuff. It just looks cheap and nasty. It took a while to work out why. The original paint has a beautiful diffuse reflectance. It really isn't specular at all, while the new stuff has strong specular behaviour.

Diffuse: no direct reflections, any light on it bounces off over a full hemisphere

Specular: glossy, lots of direct bounce, the ultimate specular surface is a mirror.

The OEM stuff is luscious to the eye, even twenty years down the road. Good paint is very important in selling motorcycles and I want to keep that sort of look even if it's out of a rattle can.

So I did some checking around the web and I might have two possibilities. PPG make a close match to the original, sold through Bunnings, paint code 223.647 (Grigio Steel Ducati) or code 0011 (Grigio Metallic). So I'll see what they can do for me, I can certainly go over the front half of the frame again and see how it comes out.

[OddDuck]

Right, no luck whatever trying to get anything to a code from PPB. Off-shelf cans aren't any better than what I've got and usually are worse.

Fine, full overcoat with the colourmatched rattle cans it is... and on the off chance, I went and got a can of clearcoat as well. Colour and clear coats were sprayed top and bottom in two setups, with the frame normal and inverted positions on the table. The piece of alloy plate I'd used for a welding tble also serves as a carry tray, so I can move the frame to the bench, put the table away and get the car in for the night.

The clearcoat has tidied it up very well, I think... pictures below. This might have given some of the luminosity I'd seen in the original paint. I'm quite pleased with this, maybe it'll work after all. Engine shims arrived this week but I'll have to let this dry for at least a day first.

Just a couple of notes, from my mistakes...

First: yeah, the main tubes are chromoly. 4130 (or what the Italians call 25-Cro-Mo-4), as shown by the way it's rusted around where the seat and tank mounts have rubbed the paint off. Chromo rust looks quite different to low carbon steel rust, I should have guessed earlier that tabs, seat mount tubes etc are mild steel and are different to the main frame.

Second: any transition between old paint and bare metal needs to be tapered as carefully as possible, otherwise it'll show up clearly when painted. I'm not going to go back and do it again - there's a pretty good chance I'll be re-welding, and it's an old bike anyway - but it's worth remembering in future.

[OddDuck]

Got onto shimming the engine cases today.

It turns out that Ducati shim sizing can't be taken blindly off the packet: the sizes vary by as much as 25 microns from nominal and if you're stacking a few of them, it adds up. Also I found that one set of shims had the 0.3mm and 0.4mm shims swapped between their bags.

I was able to mix and match for most sizes, but some shimming involved taking an oversize shim and using paper and block to thin it down. I tried a few ways to do this - bye bye fingerprints - and in the end found that double-sided tape on a slightly under diameter socket was the best way to go. The double sided tape held up reasonably well against CRC 5.56 used on the paper (to keep it from loading up) and the undersize on the socket diameter meant that I could keep tabs on the shim thickness with vernier calipers. I did a lot of rotating the socket while sanding, this kept things parallel.

Assembly once shims were prepared was straightforward: all shafts fitted to one half, gasket placed, oil pump bypass valve and spring placed, other casing half fitted over the top. The oil seal for the timing shaft was pushed into place afterwards.

I checked end floats after torquing the screws up and found everything was what it should have been:

Shift drum: 0.20 mm
Gearbox shafts (both) 0.10 mm
Crankshaft: no play whatever, 0.15 mm preload used, shaft is a bit stiff to turn by hand once the crankcases are torqued up.

I did some checking on the 0.15mm preload and it's all summed up very nicely in this post:

http://www.ducati.ms/forums/77-sport-classic/115359-main-bearing-crank-preload.html

Basically it comes down to the casings expanding more than the crankshaft. At operating temperature, there should be minimal to zero preload on the bearings, but no free play.

It's worth pointing out that the Ducati factory manual doesn't specify this, it just says "there should be no free play in the crankshaft". If I hadn't checked the Haynes manual and the forums, I'd have assumed correct shimming meant no preload but no free play at room temperature. The bearings would have been loose at operating temperature and probably suffered rapid failure.

[OddDuck]

Some more work, much simpler stuff - fitting a Nichols crankcase breather and rebuilding the goodies inside the oil pump cover. Timing belt pulleys and transmission gear both have to be locked with special wrenches and torqued up.

The transmission gear lock wrench isn't a Ducati item, it's aftermarket. It didn't quite fit but a spot of filing sorted that out.

Unfortunately I've missed a couple of seals... the big one that goes on the clutch drive gear's hub, and a smaller one that goes over the crankshaft end. Both fit into the oil pump cover and both are reasonably important - the big seal prevents clutch dust making its way into the engine, and the smaller seal controls the flow of oil into the crankshaft's center oilway. That'll be a couple of days delay but I should be able to get seals via the SKF distributor.

[OddDuck]

A bit more work today - alternator cover side, this time.

The oil seal (in the pump cover) for the crankshaft end has been installed the wrong way around, at least at first sight. Apparently they're all like this. Ducati did this until higher pressure oil pumps forced a switch to orthodox practise. I have no idea why - maybe they like controlled leakage - but that's the way it is, so that's the way I'll install the new seal. After I work out how to get the old one out... There's nothing to grip on and it's tight against the face below, so I can't lever it up. Never mind. Later. Move on.

I found out the reason that the timing shaft key had been such a pig to remove - it's a pig to install. The woodruff key just kept rotating in its semi-circular groove and then backing out, every time I attempted to install the timing gear. Very frustrating... The previous mechanic must have deliberately indented it so that it'd fix in place. In the end I found that using a pin aligned along the gear's key groove, keeping the key straight during installation, worked brilliantly. Hope that trick's useful for someone out there, but that said, use a pin, they'll bend if something goes wrong, where a needle might break and drop into an engine.

The driving gear for the timing was next, that was an easy drop in. Timing marks aligned, then spacer, collar, needle roller bearing and flywheel / starter clutch assembly were next. Alternator core and domed spring washer plus flange nut next, then I torqued them up. This is possibly the highest torque setting in the bike: 180 Nm. The easiest way to do it was to get the two handles close together and close them with by squeezing with both hands, rather than use arms.

The wrench for the alternator's permanent magnet core is worth a mention - it's a special made from machined aluminium. This is so that it's non-magnetic and won't stick.

Ignition trigger coils were next. These are supposed to be set on their bracket with 0.7 mm (+/- 0.1 mm) clearance to the flywheel rotor tooth, and aligned to the marks machined in the rotor with the horizontal piston at TDC.

A lot of judgement comes in here... Ducati didn't put any sort of absolute reference in for flywheel position relative to crankcase, despite keys / splines etc. You're down to judging what the conrod is doing relative to the barrel alignment pin, or similar. In the end I settled on a slightly conservative position, about 1 degree retarded from previous.

I suspect cheap and nasty attempts to bump up performance in the past... here's hoping it runs a bit smoother. I'm prepared to lose a few HP at the top end, I never need it on the road anyway.

[OddDuck]

I've had a problem with oil vapour and oil seepage getting out of the stator's wiring gland.

The original Ducati stator has a very nice high-temperature silicone rubber insulated twin-core lead. The lead itself is roughly 8mm diameter on the outside and seals with Ducati's trapezoidal-section O-ring and clamp gland. Mine had been in place for nearly twenty years, the rubber had crept under constant pressure, and the wiring inside had nearly touched. By the time I found that out, the stator wiring itself had failed (taking the reg/rec down with it) and the necking didn't matter anymore.

The aftermarket stator I replaced it with has turned out to work just fine in all particulars, except that the leads were covered with a loose PVC sleeve. PVC, oil, and engine heat just doesn't work. The PVC went brittle and hard. The sleeve was also open at both ends, meaning that even if gland-sealed on the outside, oil and vapour just walked straight along the inside. That's if it sealed on the outside. Mine didn't, it just collapsed under the O-ring. I had dirt and oil all over the lower left side of the engine. Nasty.

The smallish twin-core cylinder pictured is a home-made component machined out of high-temperature Tufnol. I've attempted to seal the wiring runs with silicone - we'll see how that goes - but the Ducati O-ring and gland actually do fit around the outside and tighten up OK. It's not perfect, it's skewed in the gland and there really should be a support boot for the wiring, but we'll see how it goes.

[OddDuck]

Oil seals in the case covering the oil pump.

These look easy... they aren't. The big one, 75-95-12, seems to need a press and a dedicated push tool. The small one has been inserted backwards. When it's twenty years old and it really is time to change it out, there's nothing to grip on.

The backwards thing seems to be standard practice on all Ducati 2V twins up until 1998 or so, from what I've read. If inserted normally, oil pressure would keep it tight on the crankshaft. If backwards, that seal lip would tend to float, lifted above the surface by oil pressure. Wear would be minimal, borne out by the complete lack of a seal wear mark on the crankshaft. The oil leakage would also mean that the bushing is continually cleaned, there's no risk of this turning into a sludge trap.

I tried a bearing puller on the bushing beneath - no joy. In the end I used the dremel to cut the seal wall out. A knife tip got the bend started, then the screwdriver went the rest of the way. I'll have to get every metal shaving washed out before reassembly. That's important anywhere in an engine, but doubly so here - this is the gallery feeding the conrod main bearing shells.

[OddDuck]

I had a quick go at getting the big seal out with generic hand tools and it became clear that all I'd do was to mess up the oil pump engine cover. There's no way to get enough force to bear without putting unacceptable loads through a relatively thin casting wall.

It seems that Ducati never got around to releasing a tool for this job. I've spent the last couple of days making up a dedicated, one-use tool for this job, something that could be used on the bench.

Hopefully the photos make it clear what's going on, if not, here's what it does.

Extraction of old seal: Pull plate fitted to rear of seal, grooved lip engages metal seal ring. Collar (so seal has some clearance to be pulled into) fitted over the top, then the threaded plate for the screws. 8 x M6 x 50 cap screws, tighten by hand, then go around every third screw and nip up to equal amounts. Ten minutes later the whole lot comes out, seal and all. No hammering, no gouging of the cover. Success.

[OddDuck]

... and insertion of the new seal, a generic SKF 95-75-10.

Free plate on top of seal, seal itself positioned on outer face of cover, threaded plate plain face on rear of cover. 8 x M6 x 25 / 30 cap screws and away, as before. No issues, I checked as I went and provided the screws are tightened small and equal amounts, moving around the perimeter in steps of 3, it doesn't skew.

The crankshaft bush oil seal original was 7mm thick - I've chosen to replace it with a 5mm seal, deliberately leaving a 2mm gap and lightly levering it back against its retaining washer and circlip. Not standard practice but oil pressure should keep it in place.

[OddDuck]

Gasket fitted, seals oiled, cover refitted. I put the clutch basket back in.

Loctite 510 is used on the 8 bolts securing the basket - this isn't only to keep the bolts from coming loose. The 510 also acts as a sealant. The threaded holes are open at the far end to oil.

One of the forum posts I'd seen about the cover's large diameter seal mentioned using the clutch basket as a driver to push the new seal in. Most of the way, at least. Sounds like a good idea, but this will axially load up the gearbox shaft bearing and possibly indent the ball bearing races. I wouldn't risk it myself, it's a lot easier to take the cover off and do this particular seal change on the bench than it is to replace that bearing.

Anyway... the basic clutch basket / hub locking tool shown here takes time to put on or take off, but it works. It's a lot cheaper than the two dedicated Ducati wrenches that would otherwise be needed. I keep its mounting bolts taped to it when it's not in use.

The numbers shown marked with Sharpie were done during disassembly so that plates and steels go back where they came from. It'll help with the clutch actually working properly, this time... I've had a lot of trouble with the clutch either refusing to release properly, or slipping under load. I think it's happening because things aren't sliding along splines properly. I'd taken the time to very carefully go over every steel's internal spline edge with a needle file earlier, but I'll only find out if that worked once things are running again.

The cover gasket gives approximately 4 mm of lift to the cover. Without this gasket, there's a pretty good chance of the spring cups scraping the inside of the cover (both cups and cover are marked from this).

My last note from tonight is a bit more general: I've been noticing that things wrapped in ziplock bags are coming out exactly as they went in. Stuff wrapped in rags, which was oily when it went into storage, is coming back dry. The oil's evaporating off even at room temperature. So far I've avoided rust, but that's luck - this has happened in about five months or so.

[OddDuck]

New rings fitted to pistons, via specialised piston ring pliers. I found it necessary to pull the spring out of the wiper ring, put this into the groove, then drop the ring in over the top. The other two rings were straightforward.

The cylinder bores were oiled and their pistons were then pushed into their barrels, via a ring compressor. There are much better ones than this - this is the generic Stanley tool - but it works. The trick is to wrap the compressor's ribbon of spring steel tight, fit it square and center to the barrel, and then shove the piston in fast. If you try to do it slow, the rings will catch on the 45 degree chamfer at the barrel's end and you'll have to try again.

Ducati's air and oil cooled V twin engines are unusual in that there's a cylinder base gasket, but no head gasket. The compression seal is achieved purely via a machined aluminium spigot on the cylinder and matching recess in the head. Oil seals between the two are done with O-rings. It's very easy to service, but these O-rings have a nasty habit of setting under compression and heat, so the heads have to come off again at fairly regular intervals.

I sealed the crankcase faces with a bead of Loctite 510, then the top surface of the base gasket with another bead, as per the manual. Barrel fitted, gudgeon pin connected and circlip fitted to piston, carefully. It's very easy to pop the oil control ring out if the piston slips out from the barrel. Then I found out that the new Nichols head studs are a bit of a tighter fit in the barrels than the normal Ducati studs. This got sorted out with a rubber mallet, careful tapping on alternate sides got the barrel to bed home.

[OddDuck]

A further note about the Nichols head studs... it's well worth while to check the base gaskets for fit (and take a chainsaw file to them where necessary) before final assembly. It looks like Ducati left fairly generous position tolerances for the holes in the base gasket, based on the their own studs using an 8mm diameter shaft. Those base gaskets aren't a perfect fit.

Barrels on, heads next. There's a little dowel with a neatly drilled hole placed between head and barrel, this must be to control oil flow to or from the head via restriction, by my guess. It requires precise positioning between head and barrel. I struggled a bit with alignment, again due to the new head studs. There was a fair bit of persuasion needed to get everything to close up, rubber mallet at first and then bit-by-bit tightening of the head nuts.

Ducati, and various aftermarket suppliers, sell wildly overpriced 15mm ring spanners with a half-circle cylinder head clearing hoop and 1/2" drive on the far end. These are for setting torque on the head nuts, since you can't get a straight shot at them with standard tools. Nice, but not really needed. I got a 3/8 drive set of crow's foot spanners, modified the 15mm to be a simple open ended spanner, and use this instead. The trick for setting accurate torques is to have the crow's foot sitting at exactly 90 degrees from the torque wrench. Another way of doing it is to purchase a 15mm ring spanner, a 1/2" drive socket (any size really), and weld the two together, then grind down the thickness of the 15mm ring so that you can get it in to the head.

Inlet stub pipes with stud bolt insulators were next, I needed to do a spot of filing on one insulator flange but other than that, they went straight on.

[ruaphu]

Wow, nice work OD, coming along beautifully, awesome read.


Sent from my iPhone using Tapatalk

[OddDuck]

Refitting the timing belts meant turning the engine over by hand. I'd bought a tool just for this and was very disappointed to find that whoever designed it must have never had the chance to test it... it screws in, you tighten up the nut on the collar, try to rotate your engine and instead simply unscrew the tool again. The only way it will work is if the engine is turned backwards, complete with the starter motor engaged and back spun.

The good designs use a couple of teeth to engage the small keyways left for this purpose at the left end of the crankshaft. I hacksawed and filed these in, then refitted and found that the tool still unscrewed itself. The big handle needs to be on the barrel, not the M6 nut. In the end a pair of vice grips on the barrel got the motor to turn over.

[OddDuck]

Timing marks on the drive pulleys aligned, I refitted the timing belts and checked timing marks with the belts pressed in where the tensioners go.

Something I've got to do on the next Stein Dinse order is have a look replacing at the pulley on the horizontal head... there are two different types of belt pulley used, one with a flange on the outer face and one without. It makes sense that the flanged ones are used on the timing shaft, but on the heads the flange prevents belts being fitted or removed. I think someone's managed to inadvertently swap a parts bin pulley around in a previous rebuild. In the end I had to undo the pulley and fit the belt in free air, after making sure which belt tooth fitted into which groove.

The next bit is setting belt tension. A few years ago I found this guide:

http://www.ducatisuite.com/belttension.html

There are a lot of methods of setting belt tension, ranging from the original 10 N pull tool, to sonic tools (belt resonates at 100 Hz or so), and the latest I've heard of is something to do with lasers, probably interferometry. If you're a pro or regularly redlining the engine then this is probably worth chasing up, but I've managed just fine for years with a pair of allen keys and setting belt tension by feel.

It's a simple enough method: use the allen key as a feeler gauge between the belt and the fixed idler pulley. 5mm on the horizontal cylinder, 6mm on the vertical. The problem with this method is that it's very dependent on 'feel', it's cheap but it's not precise. Tension has to be set with the motor cold.

Also at the timing position, one of the heads is under spring tension from the closing arms and it'll tension the belt. You have to slightly rotate the heads past the timing position to take this out. Have a play with belts and pulleys, you'll feel it if this tension is there or not.

The 8mm cap screws securing the tensioning pulleys are notorious for ripping their threads out. The metal used is very soft... it's not uncommon to find recoils have been installed. This is the case with all four on my bike. I used the generic M8 torque figure mentioned in the workshop manual, of between 23 and 27 Nm.

[OddDuck]

Motor now rebuilt, I set up for a lift off the stand and got it onto its feet again. Nearly had a whoopsie doing it - the slack chain for the hoist jammed into a corner between engine and U-bracket (at the rear) and started to tip the whole thing. It's a top heavy lift, the way I've done it, and if it starts to go it could get a bit dramatic. I noticed in time, relifted and got the chain clear, then I was away again.

Lifting: best done slow and with two people keeping an eye on it, from all angles. The chain bound up on the other side of the motor from me. This stuff is a pretty good reason to keep a pair of steel-capped boots around, too. The feet I've made for the engine are like guillotine blades. Very easy to stick toes or a foot under it - it's the kind of stuff you only notice once things start to go wrong.

Anyway, motor down safely, swingarm fitted. I wanted to put this in with no clutter in the way so that I could clearly see and feel what I was doing. Also, having nothing on the swingarm itself - no shock, no rear wheel - helped hugely. The swingarm axle needed a push and a twist to clear each of the four internal seal lips, but it would push all the way through by hand. I didn't need to use a drift or mallet.

There are shims used on each side of the swingarm, both to set axial clearance, and also to set alignment between the chain drive sprocket and rear wheel sprocket. These are supposed to be as close to perfectly aligned as possible, to give the longest possible chain life. This will have changed, after the engine rebuild, since I moved the position of the output shaft. I set the swingarm at the middle position, for now.

[OddDuck]

Something that I've taken to doing is putting a coating of grease over the engine bolts and both axles. There have been issues with these quietly rusting in place before - the black pitting is visible on the bolt shown - and once the rust gets stuck in, it makes very effective threadlock. I had a lot of fun and games getting the rear axle off for the last tyre change.

The frame is extremely easy to lift on or off. There are just two engine bolts, both long. Where it's possible to go wrong is that one has a fine M10 x 1.25 thread and the other a standard M10 x 1.5. The fine pitch thread screws into a threaded boss in the frame (RH rear). It'd be very easy get the bolts swapped and then to decide that it's just a bit stiff and beast the thing in... don't do this. If in doubt, try them with the frame sitting on the bench first.

The other thing about the frame is that a slender M14 socket is needed for the nut on the forward bolt. I ended up buying a 3/8th's drive socket specially for this job, my 1/2" drives just don't fit.

The next thing was getting the rear shock refitted. I'd had the swingarm powder coated, they'd managed to forget to cover a couple of the threaded holes, and I had to choose between forcing a bolt in or doing it right and clearing the threads first. A careful run-through with a M10 x 1.5 tap sorted it out.

The shock itself is shimmed at the top. This isn't in the official Ducati literature: the shock is on spherical bushings, with a reservoir mounted off-center. It tends to twist in its mountings. A pair of large diameter plastic shim washers on either side help with this. These washers are not clamped up by the pinch bolt, they just float around the central eyelet of the shock. Some people use O-rings, I've found that they don't last for decent mileages.

The other thing I did was to get a couple of high-tensile bolts to mount the shock on. Standard sized fasteners don't really work properly here - the shock's top hat bushings end up riding on the fastener threads. The bolts that I chose were sized for the correct length of plain shoulder - nearly to the welded-on nut on each mounting bracket - and excess threaded length was taken off the far ends.

Forks were fitted next, then I got the bike up on front and rear stands to get the engine stand plates off. Wheels and sidestand fitted next. The bike's now rolling stock and can be worked on semi-normally. From here it's mostly standard reassembly and fine detail.

[OddDuck]

A few more bits and bobs put back on. It looks like the PTFE tape I used on the carbie stub pipes last time mostly worked, in terms of sealing out dirt / maintaining vacuum seal. I had trouble refitting the stubs until I cut the tape back and exposed the first turn on the threads, then no probs.

The pod filters are a quick, cheap and dirty fix to get me going again for summer. Replacement airbox is still on the cards.

[OddDuck]

Chain's stuffed. One of the end links, now open that the joining link is off, has ovalled very badly. The joining link had a badly worn pin and I'd be surprised if it was the only one on the chain.

This one's going nowhere but the trash bin. I still had a play with it anyway... why not. There were a few stiff links in the thing and a couple that I needed pliers to force to move. I had a go with PB Blaster and flexing it, trying to work the lubricant in, but aside from very minor improvements it didn't seem to do much.

Granted, it's been sitting for nearly six months, and did seem to get better resting overnight after the dousing with PB. I became curious and took a stiff link apart. One side turns freely, the other was so jammed that I needed a pair of crescent wrenches to make it move. I'd been thinking I'd find rust inside. What was there was a nearly dry, tarry residue, with what looks like rust on the rivet pin underneath. The residue is quite sticky and tough, it's easy to see how it could bind a link up. The link (ruined now of course) freed up once the tar was softened with CRC and wiped off.

[OddDuck]

Getting the bike back on the road means going for a fresh WOF, the rear tyre was well and truly under the 1.5 mm minimum major groove depth, so I had to take the wheel off again for the new rubber. The chain sprocket carrier simply pulls out once the wheel is off the bike, there isn't a retainer used.

The torque pawl pins turned out to be quite badly rusted. The freshly greased rear axle came out filthy with rust. I took a closer look and realised that the entire core of the wheel is open to the weather. The axle, the spacers, the inside faces of all four bearings... it's all completely open to water ingression.

I've been thinking for a while that I should switch from washing the bike after a ride to washing it before - this tends to confirm that. Motion + heat + air movement will tend to dry it out while I ride. Putting it away post wash is putting it away with water trapped in gaps.

The pawls cleaned up fairly quickly with some wet'n'dry and CRC, then I used high-temp grease to try to cover them against rusting again. A quick squirt of chain lube at every chain re-lube should help too. I couldn't get at the rust on the internals so settled for a pass-through with a rag to get loose rust and old grease off.

While I was at it, I noticed the very careful re-weld job on the rear brake bracket - this has been perfectly smoothed over on the open side of the wheel. Looks like the bracket has snapped off completely at some point, cause unknown (folded disc maybe?). I don't have any issues riding with it - I've been doing that quite happily since I've had the bike - but it's interesting what comes up when the bike's stripped right down.

[OddDuck]

With the chain out of the way and the sprockets / swingarm etc cleaned up, I thought I'd have a check of the swingarm alignment. For best chain life, the sprockets are supposed to be perfectly in line. The adjustment is to change the shimming washers on the swingarm pivot axle, moving the entire swingarm to the left or the right.

The previous (now replaced) front sprocket retainer is pictured below. It's badly worn on one side, chewed out by the output shaft spline. I took the verniers to it and took a rough measurement of the wear: 0.4 mm on one side, 0.1 mm on the other.

Output shaft spline greased and new sprocket retainer fitted, I took a 1000 mm steel rule and had a play. The theory was that a straight edge between front and rear sprockets should clearly show any misalignment. What I found was that it's a good indicator but not definitive... the front sprocket floats on the splines, so it has to be rocked from one side to another, there's axial play as well, and also the rear sprocket misalignment shows up much more clearly than the front ever will. The swingarm is sprung open slightly so that the rear wheel will go in, this changes the rear wheel alignment as the axle is tightened, and this affects things too.

In the end the best answer I could come up with was that it looks OK as I'd set it by centering and guesswork. It's not clearly out, and that's about as good as this measurement gets.

I'd had the thought that alignment between front and rear wheels could be set by doing this and putting increment marks on the tensioner bolt heads, but that depends on the frame / headset being precisely matched to the engine.

Last note from the night was the replacement of the OEM Ducati side stand screws, with standard BZP 8.8 grade cap screws and flat washers. I've had to drill out two sets of the factory side stand screws due to their ludicrously undersized hex sockets and cooked-in loctite, that's quite enough. The side stand has to come off if you need to get in to the alternator cover, there's just enough interference for it to be a problem.

[OddDuck]

Most of the last week has been about details and the wiring loom. One of the things I've been meaning to get onto for a while has been adding a ground lead to the front subframe.

One of the things about chassis grounds is that they can can be tasked with carrying high currents. When continuity is checked with a multimeter (I did this before adding the lead) it can come back with a perfectly acceptable result, say less than an ohm. That's what happened here. This is tested at just a few milliamps, though. It may be a very different story when a headlight is being run. Current density vs small contact patches between bits of metal, that kind of thing.

So I've crimped a couple of ring terminals onto a 4mm piece of grounding wire and added this to the ground circuit. It can't hurt, apart from adding a few grams.

Crimp pliers come in two kinds: simple pliers with rounded 'squash' jaws, and the more expensive (or much more expensive) ratchet pliers shown. I like the ratchets. The crimp terminal is held on all sides and is always squashed to the same crimp - not too much, not too little.

The trouble with crimps is that the wire is open to moisture ingression and corrosion. That can be avoided by soldering the eyelet instead of crimping, but the trouble with solder is fatigue. The solder joint doesn't have any spring in it and will crack, unless the wire is supported immediately behind the joint. Swings and roundabouts, really. There's nothing wrong with either technique if done right, and anyway wiring tends to oil / dirt / corrode up after a while, no matter what you do.

The yellow leads shown in the picture are worth a mention: these are the leads from the stator to the rec-reg unit. I replaced the badly aged and loose Ducati OEM bullet connectors last summer, since apparently an intermittent contact on these bullet connectors can destroy a RR unit in short order. The gold-plated bullet connectors used are rated at roughly 40 amps, if memory serves. They're off a hobby modeller supplier, intended for RC helicopters, and were about $5 each. They don't lock, which is the only thing I don't like about them, but that's sortable by cable-tying both sides to the frame.

Reattaching tacho and speedo drive cables has to be done carefully - Ducati chose to use industrial plastic for the angle drive housing, not metal. The plastic is soft, while the thread on the cable retainer is reasonably fine pitch and in metal. It's very easy to skew the cable's retaining screw cap and cross-thread the thing. Once it's been done, it can be very difficult or impossible to get it to ever screw on straight again. It'll also rip a bit of the threads off the plastic drive housing every time it's done up or undone. Eventually it'll be impossible to get the cable to stay on because the angle drive thread will have been completely stripped. Make sure that the cable is fitted square and centered, and that the retainer cap is the same, and it'll be fine. Back-turn it to feel it click into the first thread if necessary.

Instruments refitted, I spent a while making sure that cable had enough flex length to deal with lock-to-lock turning. Same thing for throttle cables and the clutch hose. This can mean a lot of fit and try of course, it was most of a night to get the throttle cables right.

It's good to see it with the headlight back on again, but I'll test the wiring before refitting any body panels - too high a chance that I've missed a connector and have to get back in there again.

[OddDuck]

Annealing and re-using copper washers.

I've done this a few times in the past: take them to red heat, cool them down again (fast or slow, doesn't matter), clean them up and then they're good to go again.

Torch and hearth is nice... I don't have those, so I worked out how to do it on a stovetop. The stainless steel bowl in the pics is there to bounce radiation back down - the element won't go to red heat if it's left open. The bowl does get a bit hot but it's nothing serious. This is probably being a bit harsh on the element so I wouldn't recommend doing it often or for too long. As soon as the washers are red they're done, it doesn't need soak time.

Cleaning up can be done with wet'n'dry etc but there's a jeweller's pickle, used to clean up silver, brass, bronze, copper etc, and it's much easier:

http://www.regal.co.nz/category.php?sub_id=208#Pro-Craft%26reg%3B+Pre-Po+Pickle

Works fastest if warmed up a bit but will still do the job at room temperature. The washers are shown looped on a spare bit of electrical wire so that they're easy to retrieve from the pickle.

These are all for the engine. Brakes require caution of course, I'd be OK with doing this for mine but a lot of people wouldn't take the chance. New washers are cheap enough.

It's possible to get a check on the anneal when tightening up the bolt or the banjo, the washer will crush while it's being torqued.

[OddDuck]

Fitting new sprockets to the bike, in preparation for the new chain. Experience on pushbikes has been that there's no saving money here, any attempt to re-use old components is just false economy. A worn part on the driveline will simply transfer its wear to everything else. Motorcycles aren't pushbikes of course, but I could see wear on both front and rear sprocket teeth. They're cheap enough in comparison to the chain anyway, $110 for a sprocket set vs $360 for the chain, so why skimp on it.

So, pull rear wheel off bike again, swap out sprocket. Straightforward job except for the Italian English in the Ducati workshop manual, I couldn't find a torque setting for the sprocket's retaining nuts anywhere. Finally I measured the threads on the retaining studs, at M10 x 1.25, and found the only match listed for that thread: apparently the rear sprocket is a "wheel disc gear" or something similar.

This isn't the first time that this sort of thing has happened. I can see why - mechanic's English uses a lot of unusual words, it's not likely to be taught in a language class, and Ducati had to get someone in Italy to do a translation. I've got to wonder if the German and Spanish versions of the manual are plagued with the same issue. Anyway, it's a good reason to drop the $70 and get the Haynes as well as the OEM workshop manual, these delays add up after a while.

Onto the front sprocket and I found another problem: it wouldn't go on. The splines were a much closer fit than the old sprocket and precise alignment was needed... and then it still wouldn't go on. Close examination showed a burr which had somehow formed right around the inside edge of the spline. This was confirmed by finding that it would fit backwards but would not go on: it would jam up when the end of the shaft came to the end of the spline groove.

I flattened the teeth on a needle file trying to clear the burr from one spline groove and realised that the sprocket had been hardened, then had a look with a Dremel and found that none of my grinding bits would fit properly. In the end I folded up a strip of 360-grit paper and make an impromptu file out of that.

This worked rounded things off nicely, without leaving any sharp cuts or grooves to form stress concentrators. The paper would get ripped up fairly quickly, so there was a lot of re-folding. A quick clean-up with a rag and some CRC, fit-and-try, rework as needed, re-try, and success.

The spline shaft is worn. This shows up as the new sprocket being tight anywhere on the spline shaft that isn't normally used, then quite loose once it's in its final position. When I took the old spline off, there was a lot of road dirt and some rust that came with it. Possibly it's worth treating the spline itself as a lubrication point during chain service - it wouldn't be hard to give it a squirt of chain lube while I'm at the job.

This done, I refitted the back wheel and ran into a problem with one of the tensioners. The chain side tensioner bolt unscrewed easily; the brake side tensioner's bolt jammed up and needed a spanner, then it only went half as far. Hmm. It had been nearly locked up when I'd taken the bike apart, I'd done some work on it with PB Blaster, but it looked like it had jammed up again. In the end I got it out and into the vise, put some bearing grease onto the thread, and ran the screw back and forth until it freed up.

A lot of dirt came out, doing this... it had been badly rusted when I'd first looked at it a few months ago, while the chain side tensioner was in surprisingly good condition under the gunk. It looks like atomised chain lube kept the rust off on the chain side, but road dirt and brake dust did the opposite on the brake side. It was very nearly at the point where threads would rip out or the bolt would snap, when I got onto it - it looks like it's worth treating this tensioner as a clean and re-lube item every time the rear axle comes out.

I didn't quite manage to get the chain on. It turned out to have quite a bit of spare length - of course - and I'll have to take some links off it before fitting.

[Voltaire]

Are you going to fit a new ignition unit? I've been eyeing up a plug and play ignitech at Fastbikegear.
I've got an Ignitech on my BMW race bike and they are very good.
I gather the original Kukudan ( can't be bothered looking up spelling) units have a pretty horrible advance.

[OddDuck]

This one?

http://www.fastbikegear.co.nz/index.php?main_page=product_info&cPath=706_787&products_id=7290

Impressed with the price already... $400 to replace both Kukosans in one hit, and my originals are in pretty bad shape. The silicone potting's cracking and I had to bake moisture out last winter, then coat them both in silicone O-ring grease to try to keep water out again.

[OddDuck]

Chain fitting, part one.

I took the old chain and stretched it out full length on a table, then put the new one alongside to get an indication of the right place to break it. I marked this with a cable tie and did a test fit, then got the chain tool out.

The tool itself carries a couple of driving pins (for the common rivet sizes), a pair of setting plates, and a riveting pin. It's very good to work with, but I was new to this so I kept the instructions handy. Everything's got to be clamped up right. If it isn't, a pin can go sideways and break, or the chain can be damaged.

Chain now cut I did another test fit, this time with the greased rivet link in place. Positioning is about right, roughly half-way along the rear axle's adjustment range.

[OddDuck]

Chain fitting, part two.

After greasing and fitting O-rings and the plate, this has to be driven onto the pins of the joining link. It doesn't press on by hand, unlike a clip link. Pressure has to be applied to the plates but not the pins. The chain tool's clamp plates have gaps machined in for the rivet heads, front and rear, to allow this.

One catch with this operation is that there's no shoulder on the pins to drive the plate up to. It squashes the O-rings instead and that's about as precise as this gets. Following suggestions in the chain tool instructions, I measured an adjoining link's thickness and clamped the plate to the same dimension, then got the riveting head onto the tool and closed the rivets up.

These aren't done by end to end thickness, instead it's the rivet outer diameter. It's supposed to increase by 0.3 - 0.4 mm from whatever it was originally, so I took verniers again and measured before and during riveting. It can be measured with the tool in place and tension still applied.

[OddDuck]

Chain done, I set wheel alignment (roughly), then chain tension, then finalised wheel alignment.

Chain tension is supposed to be the usual 25 mm up-or-down movement, set at the tightest point in the run, halfway between front and rear sprockets. It doesn't take much eccentricity on the rear sprocket to cause a bit of variation, so it's worth turning the rear wheel a few full rotations to be sure of this point.

My wheel alignment is a bit ghetto: I just put two blocks of 2x4 on either side of the front wheel, lay down on the floor behind the bike, and sight along the rear tyre's front and rear edges on each side. It helps to be about a meter behind the tyre, if I'm too close then the near edge gets a bit blurry.

The bits of 2x4 are there to pack out the front tyre's width a bit so that there's something to sight to. The cut ends of the wood are at the front wheel's turning point so that if the handlebars are turned a bit then it won't affect the alignment too much.

[OddDuck]

Something I've been wanting to do for a while is to properly tune the carburettors. The big issue with this tuning is measurement.

Techniques: that great Aussie flick Two Hands mentions a mechanic good enough to do it by ear, but that's about all I've ever heard about that. The other common one is to run the engine to various degrees of throttle setting and hold, hit the kill switch, then pull the spark plugs out. The state of the plug nose can tell you if it's running rich / lean / etc.

Something that's become possible in the last few years is to install a wideband A/F sensor and gauge. Pricey, fair bit of work, but I'd get real-time monitoring while riding. I've done my reading and bought an AEM 30-4110NS gauge and sensor kit.

Now to install it... the gauge has to be mounted, the sensor has to be spigoted in to the exhaust, the wiring routed and connected. Straightforward enough.

The kit comes with a mild steel bung carrying the M18 x 1.5 thread needed. The idea is to drill a hole in the exhaust, fit the bung, weld it up and you're away. Unfortunately the kit is intended for the car world, where mild steel in exhaust systems is normal. It wouldn't be a good idea on the Ducati. I've yet to work out what the exhaust pipes are made from, but it isn't magnetic and only oxidised so far despite exhaust temperatures. It's likely to be a 300-series stainless steel. Any mild steel attached to this is going to have serious corrosion problems and won't last very long, so I'll have to make my own bung.

I'll also have to make two of them, one for each pipe, and screw caps as well. The reason for two is to get a sensor mounting position on each exhaust. The exhaust pipes are not of equal length, the intake tracts are oriented differently... it's very likely that carburettor tuning will be slightly different, vertical cylinder to horizontal. I can't measure one and assume the same readings on the other.

The exhaust pipes already carry screw-in sockets, with plug caps. I can't use them. The thread isn't the usual M12 (for a narrow-band O2 sensor), it's something like a 3/8ths 28 tpi, as far as I can tell. I have no idea what Ducati put these on for. There is an adaptor for fitting a wideband sensor to a narrow-band socket, but it's M18 conversion to M12, it wouldn't fit these. The vertical cylinder's socket is far too close to the exhaust port to be used anyway.

So, onto positioning the sensor and marking where the bungs need to go. There are obvious mechanical issues with clearances to engine / swingarm / fairing etc... there's a bit more to it than just those though. This document sums things up nicely:

http://wbo2.com/lsu/LsuInstal.pdf

The sensor has to be at 10 degrees or more to horizontal and 15 degrees or more to vertical, ideally 18 inches down the pipe from the exhaust valve, and not sited somewhere too hot. I had a play and marked up the best options, then took fairing plus exhaust system off the bike again in preparation for cleaning up and welding.

The gauge itself... I'm keen on the idea of vacuum-forming a housing for it, something which bolts on at the right hand side of the instrument panel. Clearances are an issue, so I'll be doing a bit of trial fitting of the positive before I attempt to form the plastic.

[OddDuck]

Taking the exhaust system off showed something a bit disturbing - there's a big flat filed and bashed into each side of the... wings, I guess they'd be called, of the exhaust system. They've been contacting the ground while the bike's leaned right over.

I've been running with the preload on the rear shock reduced almost as far as it'll go (it worked for the previous owner, but he was a bit lighter than I am), looks like it's time to find the C wrenches for the job and wind the spring up a bit. This is a safety issue - if footpegs contact the ground they'll fold, but if something solidly mounted like the exhaust does, it could unload the rear tyre. Bad things happen next.

I've been spending a lot of time this week thinking about the replacement battery box. On the OEM system, this is integral with the airbox. So is the mounting plate for the bracket which carries the coils and CDI units.

It's not easy to shift coils / CDI units to somewhere else on the bike, unless I hack into the wiring loom. For now, they're best where they are. It's a good location - warm, dry (mostly), close to where they need to be. So the new battery box will have to carry these as well as the battery.

The battery C of G is above the mounting points. The coils and CDI units just add more to the top heavy weight. So the new box has to be mounted in a similar fashion to the old airbox, side to side and fore and aft. It's easy to use the existing brackets on the frame to either side of the battery, not so easy to attach further forward.

Materials and methods: probably 1.6mm sheet steel, folding, and TIG welding. I don't want to hack up the old airbox and I can't work out how to make the shape I need via vacuum forming, so plastic is out.

I was given some 1mm / 10mm ruled graph paper a while ago - it makes it easy to draft up simple planar structures and make cardboard mockups. My first attempt (the red mockup) is a similar idea to the OEM airbox - there are wings streching forward to the original fore mounting points. It'll be strong and relatively simple to make. Unfortunately it won't work: there's a clash with the non-original throttle cables entering the carburettors.

The simpler, smaller brown battery box looks like it'll work. At this point I'm thinking of running the forward support centrally through the gap between the pod filters. From there, I could use the original mounting points, or perhaps clamp to one of the frame's front triangle cross tubes.

[pete376403]

a lithium (shorai or similar) battery is so light you could mount it on top of the windscreen and it still wouldn't affect the CoG enough to make a difference.
So, battery in the tail piece and that leaves lots of room in the newly vacated battery box for CDI / coils?

[OddDuck]

I meant the CoG of the battery box only, not the bike itself - sorry if that wasn't clear. My meaning was, if the battery box is down to just the two mounting points on either side, it'll tip forward.

I'd been meaning to refit the original battery (cash is getting a bit tight, so is time) but your suggestion sounds better and better the more I think about it. Back to sketching, I'll see what ideas come up.

[OddDuck]

I had a look at the bike last night and there's a real problem with installing a Shorai in the tail - proper brackets welded to the frame are needed.

The plan had been to vacuum-form an open top ABS box and screw this down to the existing ABS tailpiece of the bike. It would have been relatively simple to do - a couple of extensions to the existing cable harness, careful tucking and placement of everything, and done. The gotcha here is that the tailpiece of the bike isn't very well attached. The attachment points are thin, not well braced or gusseted, and the plastic itself has flowed under compression and also cracked around the screw heads. Even though the Shorai weighs just 1 kg, it's still another kilo and it's being bounced around on every corner.

Wish I'd seen this while I had the frame out, earlier. Can't be helped now, not unless I want a lot more work. Summer's coming, I'm hearing the bikes out on the good days, time to abandon perfection and just get something that works.

[OddDuck]

A bit of work over the last couple of days, cleaning up a bit of steel sheet and cutting / drilling etc in preparation for welding.

Techniques, for those interested:

Marking out was done by cutting out the graph paper design and taping down, then ruling / centerpunching where needed. The graph paper saves a lot of time fiddling with set squares and x-y positioning with a ruler.

Cutting along lines was done by angle grinder and cutoff disc. It's possible to get to within the last millimeter if the line's clearly visible and a bit of care is taken. I used a Sharpie to mark hole diameters and cut lines after the drawing was taken off, I find this tends to avoid confusion later.

Drilling the big holes was done with a holesaw, bench vise and a decent quality mains powered drill. A drill press would have been good, though. Slow speeds are needed and it's best if motors are run full speed through gears or pulleys, instead of using speed control circuitry. The motor on my drill gets stinking hot doing this and I've had to do the work in stages. I've used a hacksaw for the internal cuts between holes.

The little cylindrical objects are threaded standoffs, lathed up earlier in preparation for welding in. I'll have to make this structure in two bolt-together pieces, in order that it goes in / out with the fuel tank in place. The original airbox also carried the starter relay mounting bracket, and I'll want a P-clip for the battery vent hose, so those need to be added.

The plates are thick (this'll help my beginner welding) but heavy, that's why a few ovalled cutouts are starting to appear. The target is to try to get around the same weight as the original airbox / battery box, or at least not too much more.

There's quite a bit of gorgeous custom battery box work out there, featuring pierced designs... this is not going to be that pretty. It's just lightening via swiss cheese.

End note: isn't the only way to do this. A quick check on Trademe showed an auction offering sheet steel with laser cutting. A basic DXF file, some bucks, and I'd have had a fold-and-weld solution. That's probably the way to go next time, but for now I'll press on.

[OddDuck]

Ready for folding and welding. The passivated plate at top is the OEM Ducati coil and CDI mounting bracket.

Holesaw, hacksaw and file might be cheap and easy to set up and get stuck in, but if I do this again it'll be CAD/CAM, DXF and laser cut... or at least some kind of chassis punch. Deburring via some kind of machine would be good too.

I've deliberately left the side plates completely clear - no piercing. This is aesthetic, I've yet to see a bike with an exposed battery looking good.

I got curious and weighed the collection on my kitchen scales - they came in at 1540 g, total. I haven't weighed the former airbox yet.

[mossy1200]

I think you should make your battery box in steel as you are then use it as a mould to remake it in fibreglass.

[OddDuck]

I think you should make your battery box in steel as you are then use it as a mould to remake it in fibreglass.

It would be really interesting to have a play with fibreglass, I've never used that material before, but I'm running tight on time. Need the bike ready and running in two and a half weeks... it'll have to be this, welded up and painted.

I weighed the OEM airbox / battery box / coil mount assembly last night and was surprised to find it coming in at 1670 g. That's with the lid opened up and snorkels removed, rubber trumpets included in the box. So there's not that much change in weight anyway.

[OddDuck]

Folding the plate carrying the coils and CDIs.

The steel I've got is 3.5 mm thick, way too solid for the little mechanic's vise I've got on the bench. I carved out a channel with a 2mm cut-off disc down to roughly a third of the original thickness, then folded via G-clamps and crescent wrenches (for extra leverage).

It worked out very nicely - no curves or waves in the plate outside the bend radius. I'll have to weld the channels closed if I want to restore the original strength.

[OddDuck]

Welding the box together.

Welder's magnets are really good to have - the ones pictured can be set to any angle and also can close a 90 degree angle around the outside, very useful for a box like this since it's too small to fit normal one-piece magnets on the inside.

I tack welded, then started running the seams. Compared to the frame welding earlier, it's been an absolute doddle. Straight lines, easy access, not even any need for filler rod most of the time. Melting the parent material together is working fine. Something that helped a lot was using the welding table surface as a guide for the torch.

A while ago I'd been told about the value of good welding helmets, after today I believe it (still welding with a cheapie for now). The ability to see precisely what's happening is pretty much essential, as soon as I'm guessing then the weld's turning into a mess.

The two smaller mounting tabs were the only welds that needed filler rod. I'd left them undrilled deliberately, there isn't much margin for error with these and I'll have to mark out by fitting to the frame.

[OddDuck]

Threaded spigots have to be welded on in a few points too.

A mistake I made with the box was not wiping the panel edges down with a new rag and acetone. I'd used the usual water-soluble degreaser, but had a few spots of porosity come up in the weld from residual oil. Didn't want it to happen twice, so went for immersion washing of the spigots first, then positioned these and welded.

A couple of notes... the thermal mass of the spigot is much less than that of the plate it's welded to. It's very easy to melt the spigot rim back without connecting to the material underneath. I found that making a puddle in the plate, then walking it up to the spigot edge, tended to work best.

I made a mistake with one of the spigots carrying the coil / CDI bracket... I left the M6 cap screws I'd used for positioning and clamping during tack welding in place during the main welding.

Not a good idea. Either I managed to collapse the spigot wall a bit, or I bent the screw, or something else happened... but it wouldn't come out after the lot had cooled down. I tried forcing it and the head snapped off, leaving a few spigot threads clear and the rest of the screw jammed in. This was fixed by using the accessible threads as a guide for a 5.0 mm drill and drilling the body of the screw out, then chasing the threads with an M6 bottoming tap got the rest of it out. I've probably lost the crests off a few threads doing that, but it looks serviceable.

[OddDuck]

The box needs to be stabilised against rocking forward / back on its two side mounts.

One idea I'd had was to clamp to the bar I've installed across the top frame rails, for this I'd need a split clamp welded to a bracket to connect to the box.

Ducati use a technique of fixing threaded bungs to the frame via a weld bead. I gave this a go and found that it can be done relatively easily. Unfortunately the results aren't exactly gorgeous... a shame really. I know that temporary solutions have a habit of becoming permanent, but I'll probably have to go with this for now.

[OddDuck]

Box now in position in frame, anti-rocking bracket yet to be made.325183

[OddDuck]

I really wasn't happy with the split clamp, so remade it, this time from a decent piece of stock metal and a couple of cut-down M12 bolts. The hole was initially drilled with a 25mm holesaw, marked out to final size using a socket with right outer diameter, and then filed.

A couple of notes from the day... I did some reading about alternatives to machining up spigots (or whatever the things I've been making should be called). A lot of guys simply weld commercial nuts down to plates, but that has issues with the plating giving off fumes when it's welded. Galvanising is nasty, so is the yellow stuff seen on the high-tensile fasteners. Grind or blast first, basically. Stainless can be used but it's a third the strength of steel and apparently there are also issues with hexavalent chromium.

Weld nuts exist commercially. They're basically standard black steel hex nuts with a locating spigot on one side. The idea is to drill a hole for the spigot, fit the nut, then spot or mig weld it into place. Quick, easy, good. The trouble is getting them at short notice and in small quantities... I've never seen these on the shelf anywhere, which is kind of odd thinking about the numbers of people out there making stuff in garages.

Anyway, carrying on... Anti-rocking bracket now welded up and good to clean up and paint. It's been tried for fit and goes on OK, although it was fussy to make. If this design doesn't work out, it's still possible to rebuild this component and use the existing forward airbox mounts on the frame, with a new bracket design.

[OddDuck]

Had a first go at vacuum forming plastic today. I want a mount for the wideband AFR sensor's gauge.

Failed, but learned a bit... the technique is simple enough, it's basically one-sided moulding of plastic sheet. Heat sheet up in a frame, stretch it over a positive former (that's the mould), then use vacuum to suck the hot plastic down over the former. The professional machines sometimes bubble the material with positive pressure first, to give more uniform wall thicknesses after forming.

I went wrong in at least two areas: the plastic chosen for a first go, and the frame to hold the sheet with. I bought a polypropylene box for the princely sum of $6. It wasn't much work to cut the plain base out of it. Unfortunately the PP is a great material for injection moulding, which is why the hardware shop had boxes made of the stuff everywhere, but a terrible material for vacuum forming. It buckles, also apparently it goes soft one moment and then promptly melts the next. Very tight temperature control is needed. All I've got is a standard domestic oven. It's simply not happening with PP here.

The forming frames didn't hold up to the buckling of the plastic - quite a few of the screws ripped out. A couple of the bits of wood also buckled, and of course the paint was an issue in the hot oven. I'd seen it, thought I'd give it a go anyway, but it really wasn't a good idea to put painted wood into an oven at that temperature. Oops.

The last note from the day is the amount of vacuum used by the commercial machines: they're pulling nearly 27 inches Hg. I've got a standard domestic vacuum cleaner, it's pulling a fraction of that, but I'll have to see how I go with what I've got.

I've found an ABS tray via Trademe and will try again with that, in the meantime I'll have to make new forming frames.

[OddDuck]

While painting the new battery box and bracket, I got onto preparing the exhaust pipes for the new O2 sensor threaded bosses. I have to drill and weld, and of course they've got coking / carbon on the inside. Best to clean before welding. One of the weld zones is directly accessible (on the short 90" pipe pictured), the other is around a bend and some distance down the pipe, just before the cross.

An idea I'd been toying with for a while was to shove in some gravel, pour in some degreaser, cork all open ends and then simply shake the thing. Gave it a try today. It works, albeit slowly and with some labour. It's very much a method of diminishing returns, so I've got near enough and stopped, instead of trying for 100% clean metal. A look in the screw port next to the weld zone showed clean metal inside (it was a bit difficult to photograph properly). I'll take another look once I've got the holes for the bosses drilled.

[OddDuck]

New battery box and bracket now painted and installed.

One of the issues with steel construction (instead of fibreglass or plastic) is that I'm going to have to be very careful with cable routing and edges... if insulation gets cut or worn through then I'll start having nasty short circuits. Some stick-on cable mounting feet should help here.

I've started preparation for welding the O2 sensor into the header pipes. The very short drill pictured is a center drill, normally used on a lathe - I've found these quite useful as pilot / guide drills for general work. There was no issue using a 16mm holesaw to make the entry hole for the O2 sensor. The weld-in bungs I'd bought via Amazon and YouPost had to be filed slightly to match the curve of the exhaust headers.

The earlier attempt at cleaning with gravel can be seen in one of the pictures - it's blue inside because I had to use a LED torch to light it up. Basically the carbon's gone, but the surface oxides are still there.

[OddDuck]

Welding the bungs to the exhaust headers.

I did a lot of reading through the week about welding stainless and decided to back purge the welds - to have both sides of the weld gas shielded. The reason for this was to try to avoid embrittlement / corrosion problems later on. The stainless steel gets its corrosion resistance from a very thin layer of chromium oxide, and modifications to this oxide layer (temper zone from welding, black 'sugar' on the reverse face etc) destroy its corrosion resistance.

The gas shielding is a simple idea: run a second line from the regulator to the work and use bungs / tape / plugs / whatever to control the gas flow through the inside of the workpiece. It's important to leave open gas escape ports, so the weld doesn't pressurise. A vertical column flowmeter, with a needle valve, manages the gas flow. I managed to borrow a scientific O2 bench meter from work and checked how quickly the work purged - it turned out that, even at the smallest measurable flow rate, the smaller pipe cleared to less than 0.1% oxygen in roughly ten seconds. The larger header assembly took a bit longer - roughly 30 seconds - but cleared readily. This was at flowrates of around 1 ltr / minute. The needle valve doesn't turn on / off with the torch, so there's a lot of manual on-off while fiddling with setups.

Material compatibility is important - the wrong grade of filler rod could cause problems later on. I know the headers are non-magnetic stainless but don't know which alloy. Same thing for the bungs. I've taken the guess that they're all 304 and welded with 316 filler rod. By far the most common alloy used in exhaust systems is 304, and the common wisdom on the welding forums is that going up a grade for filler rod is perfectly fine. It's all guesswork though, only longterm service will show if this holds up.

I used a pair of M18 x 1.5 threaded plugs to seal the bungs, while welding. Unfortunately one of the threads galled on the way out, balled, and tore itself to shreds inside the bung. It had been a bit notchy going in. Should have used high-temp stainless anti-seize... It looks like the bung threads are mostly still OK, but after failing to pick the embedded threads out with a scriber, it looks like I'll have to invest in a tap to clean it up. The weld bungs have a tendency to collapse slightly under welding anyway, running a tap through them again after welding is probably a good idea in general.

The welds themselves look OK. I'm a fair way off being able to produce welds with stacked pennies, but for this they'll do.

[OddDuck]

I had success with plastic vacuum forming today - the mounting for the AFR gauge is now in place.

Setup was as previous try - vacuum box, frames, domestic vacuum cleaner, domestic oven. The plastic was some ABS, sourced as camping food trays off Trademe and cut down to sheets. The revised frames were one-piece aluminium sheets, about 2mm thick each. I didn't have a way to make the usual bulldog clips work (easy, cheap, good - shame really) so made spring compressors via long countersunk M4 screws and coil springs.

As to the forming itself... ABS is supposed to be easy to handle, with a wide forming range, but I struggled. I'd say, based on this experience, that about 2mm is really the limit for the home worker with this gear. I was using material that was roughly 3mm thick and could only just get it to form. A domestic fan-bake oven struggled with the control and stability needed. Bits of the sheet showed overheat damage despite the material not having softened all the way through, at the same time the vacuum didn't have the grunt to pull the plastic into the corners properly. There are also significant wrinkles, but I'm not sure if that'd get better with a thinner sheet.

The other thing is the smoke... ohh boy. One of these days I'm finally going to learn about bits of wood and ovens. If you're going to do this, don't do what I did and use 2x4's to space the frames upward from the nearest wire-frame oven drawer. The pine wood will boil out sap and smoke very badly (especially if it's off the garage floor and has been getting oil spilled on it). Spacers are needed, the ABS sheet will sag downwards when it's ready to go, and for this form I saw it move by 30 mm. The frames have to seal to the vacuum box, that usually means that they're flat, so something is going to have to hold them up a bit from the oven's trays. Just don't use wood. Aside from the oil smoking up, I saw the wood come out of the oven with the beginnings of charring. This happened at around 160 C, it didn't take anywere near as much heat as I would have expected.

I'm not sure how much smoke came off the plastic itself. I think most of it was the wood, but at the heat-damage stage, it's possible that the plastic smoked too. I wouldn't do this in my food oven again, put it that way... it might pass for a one-off but that'd be about it. Looks like there's very good reason that commercial vacuum forming machines exist.

That done (and windows opened) I found that the formed sheet came out of the frames easily, but the mould took some persuading. I'd made this in four layers of MDF scrounged from scrap kitchen bench board, with quite steep angles. Trying to pull the thing in one go didn't work but taking it out layer by layer did.

From there it was a simple job of trimming it via drill, wood saw, hacksaw and files. It took some file-and-fit to get it into place, but the gauge fitted in without problems. Clearance to brake lines on full steering lock is very tight but it works.

The boxy grid thing on the warning lights is an earlier modification. Ducati warning lights are notorious for going invisible in direct sunlight. The grid was made via 3D printing and provides shade at most angles so that I can still see what's going on, it works almost all of the time except for when the sun angle is directly over my shoulder.

[OddDuck]

Connecting the AFR gauge to power.

This gave me a bit of trouble... the usual story with an accessory is that mostly they can be connected on top of the battery terminals. If they have to be switched through the ignition key, it's just a matter of finding a positive line and splicing into that.

The gauge draws 1.3 amps and requires a switched, 10 A fused supply. It'd be easy to cause problems by splicing in at random and causing an overload. I've spent a few hours going through the wiring diagram, trying to understand how the loom works.

The bike's main fuse box divides the wiring into five areas:

30A - main battery line, starter motor and charging circuitry
15A - ignition circuitry, fuel pump
15A - headlight, high / low beam
7.5A - indicators, warning lights
7.5A - horn, brake lights

I've added up the electrical loads already present on the two 7.5A fuses and found that the last one (horn, brake lights) will draw 3A in the worst case operating condition. That leaves a fairly generous 4A operating ceiling for accessories. In the event of a problem causing a blown fuse, I'll lose the horn and the brake lights, but that's all... the bike will still get me home.

The horn also turned out to be running 12V full time - it's switched through the ground line, presumably to simplify the wiring. This means that it's a good place to tap into for the switched positive supply, although I'll have to be sure of which spade lug to connect to. The ground connection can be achieved by connecting a lead to the front subframe grounding point.

The best bit about all of this is that connection can be achieved without cutting or soldering - I can use an eyelet for the ground and a bridged spade connector for the positive, so I don't have to hack up the loom or use a soldering iron to change anything later. I've chosen to use a 2-way connector rather than direct leads, so the connector can live on the bike permanently and I can tap in as and when I need the supply in future.

The AFR gauge is intended to go on for carburettor tuning and maybe a couple of decent runs to check engine behaviour, but once tuning is done I suspect it'll just turn into a distraction. I'm also keen to use it on other vehicles. It'll be good to keep the option of removing it easily.

The M18 x 1.5 tap arrived today - I got the exhaust bung cleaned out with a makeshift tap handle (via the socket set) and a plug fitted. Then I sorted out the last connections in the wiring and refitted the fuel tank.

[OddDuck]

Pulled the plugs, set kill switch to off, and cranked the starter motor until the oil level stabilised and the oil pressure warning light went out. Then I refitted the plugs and HT leads, put some fresh petrol in the tank and gave it a go.

Some cranking, one backfire, and then she ran. Idle's going fine. AFR gauge indicates 11, header pipes are getting stinking hot, so I think some rough driveway tuning is a good idea before going anywhere.

[OddDuck]

A bit of have-a-go carbie tuning... starting with removal of my homemade spacer plates for the inlet trumpets. These were needed for the old airbox - the trumpets weren't quite long enough as supplied, the airbox couldn't be sealed properly and there was a problem with road grit getting into the carburettor bowls and jamming up the needle valves. This caused the engine to fill up with petrol overnight, flooding the exhaust sytem as well. I had to throw the oil away. This is why proper sealing of airbox / inlet system is essential for carburetted bikes. It's not for vacuum leaks (not before the throttle plate or butterfly, anyway), it's against the dirt. Switching to pod filters means the plates and gaskets can go into honorable retirement.

My first go at tuning was simple enough: set the slow fuel screws to 1 turn, turn out the slow air screws to 2 turns. The AFR gauge is now reading about 12 - 13 between idle and 1/8th throttle, so I'll have to go in again. I don't want to go higher on the throttle with a free-revving and just rebuilt engine, though - until I'm on the road again, the higher throttle settings will have to stay as they are.

[OddDuck]

Bike's built up, running and legal. Have WOF, will ride.

There's still work to do. There's the usual shakeout of adjustments after a rebuild. I want to have a look at carburettor tuning. The fuel level sensor is still waiting on replacement (I've been using the tripmeter for years instead). That kind of thing. It's niggles instead of biggies.

Bike's rolling, though...

Thanks to everyone for your support and help through this thread, it's been a blast and I have learned heaps. Hopefully I'll be meeting a few of you out there this summer :)

The winter layup is over. Time to go have some fun.

[SVboy]

Fascinating thread to follow thank you Sir. You are an inspiration.

[insomnia01]

Awesome read :Punk: thanks for sharing

[OddDuck]

Thanks guys - it turns out that there's further comment worth making, so I guess that although the layup is over, the thread goes on...

I'll start with the insulator spacer washers I'd made up for the inlet pipes running between carburettors and cylinder heads.

The problem that I was trying to solve was how painfully loud the bike became if it ran low throttle / low RPM for any length of time. Traffic, town, even periods of time in 50 zones would go from embarrassing to painful, and in the heat of summer it'd get flat out ear-ringing nasty, even with earplugs. It was bad for me, it was bad for everyone around me. Must get bike quieter.

Repacking mufflers hadn't done it. After a while I realised that the noise correlated with the temperature of the inlet pipes, when these were cold the sound was OK, when they were hot, the problem occurred.

I spent a while going through the numbers on these and calculated that roughly 70% of the engine heat conducted to these came in via the M8 stud bolts - not through the much greater surface area of the 0.4mm paper washer. Top hat washers for the stud bolts were what was needed, not a thicker gasket or insulator spacer plate.

I am very pleased to say that idea + theory + numbers + making something and trying it = success. Problem sorted. The bike's kept the bass but it's lost the hearing-damage ringing it was making before.

[OddDuck]

Stock airbox, opened lid (with K&N filter) vs K&N pod filters.

The theory, based on everything I've read, is that stock airboxes might look pretty utilitarian but tend to win over pods. Pods are fashion statements, not true go-fast accessories. You get 5% more at the top end, but lose low and midrange torque and power - and that's where most real world riding happens. There's also more induction noise, plus carburettor re-jetting becomes necessary before lean conditions cause engine damage.

At least, that's the theory.

I've had the bike running on a few carbie tuning runs (more about that below) and it's early days yet, but the result seems to be that the pods actually don't breathe any different to the stock airbox. In a lot of ways they're significantly better.

Getting in for carburettor adjustments / sorting cables / etc is a lot easier. Induction noise has actually reduced. There might be a very slight reduction in bottom end / midrange torque, but I'd need dyno runs to make a call on this. I honestly can't tell by riding it.

One improvement has been how smoothly the motor runs. The stock airbox runs super smooth at some RPM, a bit rough at others. The pods have smoothed this effect out very nicely. I'd guess that non-equal induction intervals in a shared resonant airbox would cause this; one cylinder robs the other, depending on RPM, airflow and resonant waves. The fix is to separate the intakes.

Top end power is unknown as yet, but for now the conclusion is that pods (on this bike) work just fine.

[OddDuck]

First few days of carburettor tuning with the AEM UEGO wideband O2 sensor and gauge.

Initially this was bloody dangerous.

I don't have a dynamometer so the method of tuning is: find road, ride it, monitor gauge, come back and fiddle with carburettors. Repeat until happy.

Or in hospital / dead, of course... it is very hard to not get distracted by the readings, while riding, while navigating curves and traffic and idiots pulling out, etc etc. It's the same effect as religiously checking your speedometer so you don't get done for speeding, only it's at least twice as bad. This'd be a whole lot easier if I lived close to a quiet 100 K country road, but the closest I've got within reasonable distance is an urban motorway.

Making life more fun, the carbies were badly tuned at first (of course) and when they're like this, the gauge reading leaps around like a demented ninja. Very distracting.

As to the tuning itself... One of the reasons that I bought the Keihin FCR 41's was the ability to adjust. It's covered quite nicely on this page:

http://www.ducatitech.com/2v/inside_fcr.html

Basic settings and initial tuning are described here:

http://www.bikeboy.org/900SSwithkeihinfcr39and41mmcarbs.html

I'd spent the last two days trying to tune the carbs from idle upwards. I did it this way because before I can go fast, I have to be able to go slow. I didn't want sustained lean-outs. It'd suck to cause damage to the motor. Softly softly, catchee monkey, that sort of thing. I'd go for a short ride at 50 k's, come back and turn either the slow fuel screw or the slow air screw, go for another ride, repeat, and so on. On the second day I was onto the needles, trying to tune from 1/8th throttle upward. Unfortunately it didn't work.

The problem with this sort of tuning is that it's very easy to converge to the wrong destination. There are simply too many variables. Even changing just one setting by one notch at a time won't work. The carburettor has to be tested the whole way between idle to WOT in order to gain decent information. There isn't really a safe way to do this, it has to be roughly set up and then monitored the whole way through the throttle range with the engine under load.

The booklet from Keihin which came with my FCR's show that there are four broad tuning areas within the FCR 41 carburettor's range, all set by throttle:

Closed to 1/8th: slow fuel screw, slow air jet

1/8th to 1/4: slow air jet, needle position

1/4 to 3/4: needle position and main jet

3/4 to WOT: main jet.

Engine RPM doesn't really come into it. That's the whole point of a flatslide carburettor: it tells the engine what to do, not the other way around (as it is with CV's). Unfortunately this business of four areas (and various carburettor circuits) is simplified. The truth is that there's massive overlap of the circuits.

This page goes into a lot of detail about tuning these:

www.factorypro.com/tech/tech_tuning_procedures/tuning_FCR_Burns,Pat.html

The major point he makes (and after the last few days I believe him) is that the WOT result has to be obtained first. You've got to get that main jet right. There's no point in playing with needle settings (or the choice of needle itself) before that's done. Regardless, I'm riding tomorrow and over the weekend, something needs to be done temporarily while jets are on order.

I've gone for the Sudco out-of-the-box settings as a starting point and then tried my tuning methods from there, moving only the needle position and leaving the slow screws as suggested. My current opinion is that the slow jet is too rich and should be reduced a bit, and the main jet is far too lean and needs opening up.

Currently I'm on these settings:

155 mains, 200 main air jet, 60 pilot, EMT needle on the fifth notch from top, slow air screw 1 1/2 turns out and slow fuel screw 3/4 turn out.

The AFR gauge indicates ratios of 10-ish at closed throttle, 11 - 12 at up to 1/8th throttle, 12 - 15 between 1/8th and 1/4, and 15+ above 1/4 throttle. The engine gets progressively more lean as the throttle is opened further, hence my belief that the main jet is badly undersized. Raising the needle can only go so far.

That said... checking gauge readings and fiddling is working. It's working amazingly well. The bike has never run this smoothly before. It gets better every time the carbs get closer to proper tune. Gauge readings are settling down, too. There's a lot less jumping than there had been when I started. Provided I ride normally, the bike should be perfectly OK to ride over the weekend.

The pics below show the gauge on startup: it insists on displaying the magic number of 14.7 while the sensor heats up. I've done my reading and this is very much an ideal ratio, obtained with complete combustion of perfect fuel. In the real world, fuel's got additives, combustion doesn't get very long to take place, and ratios of 13 to 14 are probably the best place to be in terms of economy, power, and safe engine operating conditions.

I'll see about ordering some more jets and tuning from there.

[OddDuck]

On Saturday I had a bit of a knock... out for the first ride of summer with friends, and before the first tank of petrol, the bike broke down. Charging system failure. I hadn't gone over it during the rebuild work, I'd just refitted it.

She's laid up again. There's about 80 miles on the clock since rebuild.

I spent much of the weekend doing a tidy up in the garage. Six months to two years worth of trash got hauled to the tip. I got the bike stands hanging off the wall so they're to hand for easy use. That kind of thing. I couldn't bring myself to look at the bike properly, let alone get back to work on it, until last night.

Unfortunately this is part of this kind of work. There are ups and downs. I mean, it's really not that big a deal in the great scheme of things, it's just to have it happen so soon after getting back on the road... it really did feel like I couldn't win, for a while there. This is the kind of thing that gets people very upset, being upset means IQ replaced with emotion, which is why when this stuff does happen it's vitally important to take time off until calm again. Don't make any decisions, that kind of thing. Difficult to do when you feel like you've let your mates down, though.

My planned bike trip had been postponed anyway. One of the crew had also had issues with his ride, only sorted on the day we were supposed to go. I'll have to see what consensus is, but everyone's already pretty fed up with dramas mechanical and electrical. It might be smarter to postpone until early next year and ride with proven bikes.

[OddDuck]

And the fault itself... the charging system isn't.

Diagnosis for this is easy: take a DVM (digital voltmeter) and measure battery voltage, at the battery terminals. Run the engine. Voltage should be around 12V at idle and increase with RPM's, holding at a maximum voltage after about a third to halfway through the rev range. This test can get quite loud so keep the neighbors in mind. What I saw was 12 V, then more 12 V. No response to revving.

Before anyone says anything about 'crap Ducati electricals' neither the stator nor the RR unit is OEM Ducati. They're both Electrosport aftermarket. Ducati originals are still available, but they're big money (450 Euros for a generator anyone?) and I simply didn't (and don't) have the grand and a half necessary to get stuff in the branded bags.

So, before going further:

What is the fault?
Where did it happen?
How did it happen?
Is everything else OK?

I've got to investigate completely before making any decisions. Electrical fault finding demands a systematic, step-by-step approach. It's pedantic, it's slow, it can be infuriating. It's got to be done, though. Miss one detail and I'll never sort it out.

I went and borrowed the Haynes manual again. The first line in charging system problem diagnosis was unexpected: check leakage current through the system with the ignition off, by putting a current meter onto the battery negative terminal and seeing how many milliamps are trickling away when the bike's standing.

Allowable is 0.1 mA. What I've got is 13 to 30 mA (it cycles up and down) with accessories attached and around 8 mA steady with the bike-only wiring loom. This means I've got a short somewhere in the loom, as well as accessories causing a problem. Both of these issues have to be traced and fixed, otherwise I'm in for more problems further down the line.

The stator is easy to test for continuity: detach the two bullet connectors to the RR unit and check for ohms through the winding. Mine is coming up open circuit at all resistance ranges. The winding has failed. I'll have to drain the oil and get the left hand engine casing off to get at it. That'll be tonight's job.

Testing the RR (rectifier-regulator) involves checking the input rectifier diodes for forward conductance, using the diode setting on the DVM. There are four measurements to make (a three-input lead RR would have six):

- yellow input to red output
- red output to yellow input
- yellow input to black (ground) output
- black output to yellow input

These should all come back with 0.400 to 0.600 V showing on the DVM. That's forward voltage through two functional diodes. In this case they don't, a couple are testing higher, and the epoxy potting on the unit is showing that something within has cooked itself.

I was halfway through these measurements when I realised I'd made a bad mistake installing the RR unit about a year ago: I'd never understood that the ground line is through the casing. It's not through any of the plugged leads. I'd just assumed that it was, after finding that trying to work out the wiring schematic made my head spin.

This time around, I've got my head around the wiring diagram and can work out what's happening. The Ducati workshop manual's electrical schematic makes it quite clear that the 30A return for the ground line is via the eyelet that tags onto the RR casing, where it mounts with a pair of M6 bolts... it's pretty basic. I can't believe that I missed this earlier. It's been a while, I've long since thrown the paperwork that came with the RR away, but I'm fairly sure that Electrosport don't spell out the need to scrape the paint back for the ground connection.

The positive connection carries up to 30 amps. Current goes in a loop, so even though there's no potential showing, there'll be 30 amps on the ground return line, too. That means scraping paint back on the RR, cleaning paint out of the threads of the mounting tab on the frame, using a clean new bolt - in short, taking care to give a clean connection which can handle high current. I've got a couple of spots of slightly shiny metal. That's it. There's no way it's handling high currents properly, although it'd test OK for ohms with a meter.

There's a shift in DVM's in the photos - on the basis that I'll be doing a bit of work, I decided to update my tooling and went shopping. It turns out that you get a lot of multimeter for your buck these days. This one was chosen because it'll test inductance, quite an unusual feature which is very helpful if measuring coils.

[Voltaire]

How do you find the cold starting with the FCRs'?, mine is a pig to start with its 39's and been thru the carbs and settings and they are ok.
I'd say your electrical problems is the regulator if the alt windings are good.

[OddDuck]

How do you find the cold starting with the FCRs'?, mine is a pig to start with its 39's and been thru the carbs and settings and they are ok.
I'd say your electrical problems is the regulator if the alt windings are good.

Starting: not sure of your setup, but if you have the tank vent breather line just tucked away, try routing it into whatever air intake system you're using. The tank fumes will act like easy-start. It'll help. I haven't had the chance to set this up with my pod filters yet but it's on the list.

The other trick is to walk up to the bike and twist the throttle a few times before turning the key. Use the accelerator pumps to squirt some petrol. Give it 30 seconds to build up some vapour and try starting then.

My FCR's are set up with 60 slow fuel jets... they're running very rich, around 10 - 11 AFR once warmed up, and dropping below 10 if the bike's stopped at the lights or similar. I'm pretty sure there's a tradeoff between starting and closed to 1/8th throttle running.

Electrical problems so far look like both reg and alt are gone. Alt's testing open circuit, and the reg diodes aren't coming back evenly.

[OddDuck]

Right, got the alternator cover off. I've found the fault and it's 100% mine... I managed to completely forget the two cap screws which hold the stator into the cover during engine reassembly.

The stator has moved inboard from the cover and started skidding on the flywheel. The windings have been cut away to flats in a couple of points. A lead seems to have been cut as well.

Wouldn't have found this without investigating, wouldn't now know about the grounding issue on the RR, but it's still a very mixed blessing. At least it isn't a big deal getting the cover off and on the engine. The gasket is reusable, within limits.

I'd kept the previous stator and put heavier lead wires onto it, I'll get onto fitting that a bit later on. For now I need to sort out a replacement RR unit and get that on its way.

[OddDuck]

RR unit ordered, jets ordered. I spent tonight getting the previous stator (rather higher quality than the Electrosport unit, I think it's OEM Ducati) back into the cover and onto the engine.

The revised leads are furnace heater element connector wire. This stuff is rated for service at high temperature, high current, plus I've increased the cross sectional area from the original leads. High quality wiring is needed here, normal insulation really won't cut it.

Look for chemical stability, temperature ratings to 200 C, that kind of thing... and it's got to survive protracted immersion in engine oil, which can lead to hardened and then cracked plastic with most of the common cable insulation materials. PVC certainly doesn't survive, nylon's marginal at best. I am crossing my fingers with these stator leads because of this issue, unfortunately the only way to find out if this cable will work is to try it. That said, it's glass fibre insulation over silicone rubber. It should make it.

The same problem comes up with securing the leads. Vibration or mechanical force really can't be let anywhere near a soldered joint, especially not at this operating temperature.

One of the photos shows the leads tied into place with a twist of enamel-insulated transformer winding wire. I couldn't find anything else that I was confident would survive. Most cable ties are Nylon 66, maximum service temperature of 80 C, and not rated for immersion in engine oil. The stator windings are enamelled copper, I know they'll survive, so this particular tie should work. I've taken multiple turns to try to broaden the contact area and avoid cutting into insulation.

Bolts were checked for length and fit - I wanted the maximum number of threads used, but also to be sure about tightening the stator into place against the metal below. Loctite 222 was used, as per the workshop manual.

Another concern was sharp corners on the casing cutting into the leads and shorting the windings out. The shadow of the previous leads can be seen if you look closely enough; this shows the leads folded into a smoothed portion of the casting. Should be OK.

My cable gland assembly is back in place. Drilling for a larger cable diameter didn't work. I had to file the holes in my two-core bung out to admit cables from the sides; silicone goo was needed to seal it up against leakage.

I've found that it's helpful to use the cover removal tool when refitting. It's possible to put the cover back on slowly, instead of watching it leap into place when pulled by the magnet.

[OddDuck]

I've spent the last couple of nights indulging my curiosity and digging the potting out of the failed RR unit. Apologies for the wall of text below, this does get detailed.

This wasn't easy... there's a hard layer on the surface about 5mm deep which really wants a drill or rotary burr, then after that it goes a bit rubbery and it comes off readily with a broad-bladed soldering iron. There's smoke, there's dust, it's generally stinky and nasty. I can't see this as being good for a person's health so I don't recommend taking this up as a hobby.

I've also been doing my reading and looking at circuit schematics. This helped greatly with understanding what's going on in my former RR. There's a catch, though. The more I learn, the less I like what I'm finding out. Highlights below:

1) if it's potted, chances of repair are about zero
2) potting covers up cheap build quality very nicely
3) there are no fail-safes of any kind; the first thing going wrong will kill it
4) it's built to only just work, components are tiny and so are internal conductors
5) the casing's anodised finish really screws up the ground connection for the unit.

Seriously, it's crap. Unfortunately so is just about everything else on the aftermarket, as far as I can tell. Giveaways are cheap PVC sleeving and cheap bullet connectors which are clearly under-rated for the current passing through them, going to wiring which is a bit on the thin side.

Now this is idle speculation, but I think there's good reason for this. There just isn't much emotion driving purchases in the RR market. We get excited about mufflers and exhaust systems, we love anodised aluminium bling (well, some of us do), we'll pay silly money for go-fast accessories like carbon fibre huggers, but as long as the battery is being charged, why pay any attention to the RR unit. It's not exactly a glamour item. Buying a new one isn't something we look forward to; it's just another bill to pay.

The market, therefore, sets a price. The manufacturer's margin is the difference between that price and however cheaply the unit can be made. The difference is sweet profit, so they're made cheap, cheap, cheap.

Most of the schematics I've seen follow the same pattern as the unit I've just stripped:

There's a permanent magnet rotating on the crankshaft. It's encircled by a winding, coiled on a set of stator plates. That winding is fed, via leads and connectors, to a set of rectifier diodes. These diodes are bridged by silicon-controlled rectifiers, which (in a controlled manner) short these out, dumping excess voltage to ground. The rectifier feeds sensing circuitry (this controls the SCR's) and then outputs main current to the bike and charging current to the bike's battery and ground. There's usually a sensing lead back from the battery, to help control the SCR's.

The construction does pay a lot of attention to heatsinking. The PCB on the base is an aluminium plate, overlaid with circuitry on top and thermally connected with heat sink paste to the inside of the finned aluminium casing. Components that generate heat are nicely spread out, to avoid hot spots.

There's quite a lot that could be there but isn't, though. If a generator coil is disconnected suddenly, there's what's called inductive kick-back. The stored energy in the stator coil's magnetic field discharges with a bang. It can be several hundred or even several thousand volts. Loose connectors, bad wiring etc can lead to an intermittent connection, and this will momentarily disconnect the stator coil. Result: kick-back, and fried rectifier diodes or SCRs. One loose connector will knock a $250 RR unit straight into the bin. We accept this situation as normal.

This is avoidable. Tricks can be done with clamping zener diodes. The inductive kick-back spike can be made to bypass the circuitry safely. That safeguard isn't there though... Neither is any kind of over temperature protection. I'd been reading accounts of Ducati superbike owners who have had up to five RR units fail, due to traffic / stoplights / hot summer days / positioning inside bike fairings close by exhaust headers / no provision for cooling beyond slipstream. In this situation a thermal cutout is needed. That's not there either, much like some kind of current limiting short circuit protection for the RR output. Fuses aren't exact devices, it can be more than twice rated current to make them blow, but sustained high current will definitely cook the RR unit over time.

I'd checked leakage current on the bike again - that is, current between battery negative terminal when disconnected and bike grounding lead. This time the leakage came in at just 0.1 mA, inside specification for a healthy wiring loom. This happened with the RR unit removed and everything else still in place, so that's where the 8 mA leakage was happening.

I've confirmed that a good, clean ground connection to the RR casing is needed. I'm also satisfied that the unit pictured failed with the stator. The bike's wiring loom is OK. Replacement of both stator and RR, together with reliable connectors and cabling, will see the bike running again.

[pete376403]

Shindengen mosfet RRs are considered one of the better options. Higher-end Jap bikes (ie R1 etc) have them. They are being sold as a retrofit item to replace plain old diode rrs http://www.roadstercycle.com/Shindengen%20Mosfet%20Regulator%20about.htm

Also, where is the rr located on the bike. Is it in an airstream, or hidden away somewhere? ON the 1100 Suzuki, the original location was under the battery box, just above the swingarm pivot. I relocated it to the frame downtubes, just below the steering head, to get it exposed to better airflow. hasn't hurt and might have helped.

[OddDuck]

Thanks mate - since I've confirmed the grounding connection issue, and it's now a known quantity, I've already gone ahead and ordered a direct replacement from Electrosport. It's not a flash RR by any means but once again I'm on a clock and have to go with what I know. In parallel I am looking at design and build of my own RR (with safeguards) but that's one of those projects that'll probably blow out in terms of difficulty.

The Shindengen mosfet does sound good... that looks like the way to go for a spare on hand for the next time the Electrosport craps out. Cheaper and way easier than DIY.

Placement is lower front of the frame, directly behind and underneath the lower head bearing. It's right in the path of incoming air and nowhere near the horizontal head or exhaust header; placement is actually pretty good as far as cooling goes, even with the bike stopped.

[Omega1]

Yep I can vouch for the Mosfet RR's just replaced the OEM RR on my 03 Speed triple with one from a R1 the battery wouldn't charrge. It was a model FH020 luckily for me Triumph supplied a simple link lead to fit the new connectors and connect to the OEM harness plug and play thank God. very happy the Stator is all good and I hopefully wont be stranded again, heavy bike to push home....

Cheers

TC

[OddDuck]

Unfortunately I'd already ordered a replacement Electrosport ESR515 when I saw the replies.

Fastbikegear have the right Shindengen for the job:

http://www.fastbikegear.co.nz/index.php?main_page=product_info&products_id=6242

Looks like the way to go if there's another failure. In the meantime I've fitted the Electrosport, having properly taken the anodising off the mounting points and confirmed a decent ground connection.

I'd managed to borrow a current clamp meter, so had a play with this while the bike was running. Interesting numbers in the results:

Starting current (measured at the battery's negative terminal, as per photo) 70 A peak, 60 A continuous dc with starter motor engaged.

Alternator output current at approx 3000 RPM, 30 A. It was much less than this with the engine idling, roughly 5 - 7 A.

Rec/reg output to bike wiring loom, very approximate 10 - 12 A, highly dependent on lights, battery charge state etc.

Charging current to battery: slightly positive at idle with lights off, slightly negative with lights on, although it went positive again very quickly with some RPMs. Roughly 5 A at 3000 RPM, but I suspect that this will drop very quickly as the battery charges. Noticeable headlight flicker at idle.

While I was at it, I had a look at the conductor size and count of the various wires used through the generating system. I'm curious; I also want to be reasonably sure that it'll be reliable.

Current carrying capacity of stranded conductor isn't an exact science. There are tables available, but they're very approximate. A lot depends on the installation conditions of the conductor. If it's in an enclosed box, thickly insulated, bundled with other conductors, in a hot environment and so on, then not a lot of current can be put through it. If it's on its own and exposed to a cooling airflow then a lot more current than the tables recommend can pass. A lot of this is try-and-see, it's experience and iteration, with the tables used as a starting point.

Fastbikegear have a simplified table for automotive wiring: http://www.fastbikegear.co.nz/index.php?main_page=page&id=19&zenid=1dea8oq911i6d8uo917bp8b5g1

The thinnest conductor I've got between stator and RR is 17 Ga, rated (conservatively) at 19 A. That's on the Electrosport RR, as issued. It goes into potting so there's no chance of uprating it. Everything else in the chain is 16 or 15 Ga, better but not up to the 30 A required, according to the table and my rough measurements.

On the face of it, the Electrosport leads are badly undersized. The rest of the system looks marginal. However Ducati's OEM system ran just fine with 16 ga wire for years. My other Electrosport RR's all had 17ga wiring and there were no problems with that either, so I think I'll be alright. There's plenty of access for air cooling via slipsteam.

The photo of a twist-together-and-solder wiring joint is included because I'd thought it might be useful for someone out there: halve the strands and do a twist on each side instead of just one. It tends to go together and stay together much better than the usual single twist. It's still not as neat as an inline crimp of course, and also the solder joint is vulnerable to fatigue and shouldn't be flexed or subjected to vibration.

An interesting side note is that twinned leads in the stator are used. This looks like a basic Litz wire setup. Parallel conductors which are insulated from each other are used to minimise skin effects at high frequencies, that is, most of the current moving from the core of the wire to the skin, reducing conductor capacity. The bike's crankshaft can spin up to 9000 RPM, with generator output matching that frequency. Presumably it was worth doing.

Anyway, with my stator leads... 30 A is quite a bit of power. It looks like the trick to keep in mind is simple: don't rev the hell out of the bike at the lights and I should be OK. In the meantime, the bike's charging again, that means it's fairings back on and go out and ride.

[OddDuck]

Out and riding today! 300 miles or so.

In terms of how the bike's going... no issues with battery charging. There were a couple of minor engine issues, I'll detail them for anyone else doing rebuild work.

Clutch: had a spot of clutch slippage. I think this is happening if the plates bind on the hub or basket and then skew, so there isn't proper loading across friction plate and steel faces. The fix is to unload the clutch and then squeeze the lever a few times, to get the stack to squish down properly again. This can be done by shutting down and putting the bike into neutral, or even while rolling by pulling the clutch in a few times. Matching throttle and velocity helps.
Neutral isn't any easier to find, either. I presume that the clutch will settle down over time as everything beds together.

Gear change: much improved post shimming, but I still had a false neutral going from 4th to 5th. It's a problem with the gearbox design. The shaft carrying 5th and 6th gears rotates slower than the shaft carrying 1,2,3 and 4. It needs longer for the drive dogs to engage properly. The fix is in the rider: use a dwell period when changing gears instead of punching the lever.

Carburettor tuning: still waiting on those jets. In the meantime I'm running rich when tootling around through 50 zones, and increasingly lean in 100 zones. Unfortunately that can't be helped without those parts, time to call Cycletreads and see what the story is.

Aside from that - I have the first bugs of the season to get off the leathers and it's damn good to get out again. My reflexes have suffered a bit over the layup - too much driving a car - so I'm taking it easy until I settle into the bike again. In the meantime I'm perfectly happy to pootle and gradually work on the chicken strips.

[OddDuck]

On the Monday I decided I was fed up with waiting on Cycletreads and so I jumped onto Google and then Amazon and went shopping.

It turns out that EBC Brakes sell (in partnership with Abax Engineering) several jet kits, for the various Keihin flatslide carburettors. A little reading to confirm which kit to order, get the credit card out and pay for the fastest shipping, and it's here on Friday night. This is a full kit, two of each, every size from 165 up to 238, and pricing (even with fast shipping) was very good.

Straight down to the garage and into it... Something that might be useful, not carburettor related, that I should have mentioned earlier: it's quite easy to bundle the cables going to and from the CDI units and coils together. It packages nicely and runs neatly past the throttle cable pulley assembly. This is how Ducati arranged the lines, or at least it's how the bike was when I bought it. It's not a good idea to do this. I've separated the HT lines from the pickup coil lines instead, getting as much of a gap between the parallel runs as possible.

The reason for this is inductive and capacitive pickup between parallel conductors. This is a very well known problem in electronics - if you have two conductors running side by side, and you fire a pulse down one, you'll get a small pulse on the other. Magnitude of that pulse depends on how close the conductors are, the length of the parallel run, rise and fall time of the pulse, and the pulse peak voltage and current, plus a host of other variables like capacitive dialectric value between the lines.

Where this is relevant to bikes is that this effect can really mess up how the bike runs, due to interference with ignition timing and spark strength. If the pickup coil lines are too close to the HT lines, the false pulse on the coil pickup line generated every time the plugs fire will lead to a small discharge on the CDI unit through the coils. That means both a false spark, if that pulse is strong enough, and reduced energy for the real spark when it's time to fire properly.

Fix #1: separate the HT leads from the pickup coil leads.
Fix #2: put a grounded sheath braid of some kind over the pickup coil leads, to provide screening.

Anyway, after all that - the bike ran one hell of a lot smoother once I'd applied Fix #1. I didn't bother going as far as #2.

And back to carburettor tuning - fairings off, tank up, and I was very pleased to find out how easy it is to change main jets on the FCR41's. There's a cap on the base of the float bowl, sealed with an O-ring. A 14mm spanner takes that straight off - keep something handy to catch about 50cc of petrol, there's no drain on these carbies - and then you have access to the main jet with a standard 6mm ring spanner. A 6mm socket is useful for spinning it on or off, too.

Petrol on hands is an issue. Unleaded has a lot of carcinogenic / neurotoxic nasties in it, things like toluene and benzene, and I've heard too many stories about people coming down with chronic conditions from repeat exposure to chemicals to be casual about this. I've already got weird dry, peeling and cracked bits of skin on one fingertip pad from something, probably working with CRC while papering valve shims down. I tried working with dishwashing gloves (having run out of nitrile disposables) but these went super slippery with petrol and then broke up. In the meantime I kept going... one exposure I can live with, but I want gloves for the next time.

Anyway, I switched from 155 mains to 190's, changed needle clip positions from 5th back to 3rd from top, and went for a ride. The AFR gauge now tells me that it's rich at closed throttle, about right at 1/8th through 1/4, then progressively more and more lean further through the throttle range. It went right out to 18+ while climbing a hill at 80 k's. That's really not good. When I came back I realised that I didn't have a measure for what the throttle is doing - I've just been going on feel - hence the masking tape / Sharpie throttle position measure.

For now I've tried putting the idle mixture adjustment screw back in by 1/4 of a turn, leaving the slow air jet alone, and shifting the needle clip position to 4th (middle of the needle range). I haven't had the chance to test the new settings yet.

[OddDuck]

A few more tweaks...

Slow jet: 60
Idle mix screw: 1.25 turns out
Slow air screw: 1.5 turns out
Needle clip: 6th from top
Main jet: 212

Target AFR mixture: 13 to 14

Throttle position vs AFR readings:
Closed - 10 / 11
1/8th - 11 / 12
1/4 - 12-ish
1/2 - 13 / 14
1/2+ - unsure, probably still a bit lean.

The masking tape and Sharpie throttle position gauge is helping.

It's starting to look like a dyno or a legal top speed track is needed to go further. The accelerator pump throws a 30 second transient into the readings - the bike runs rich while opening throttle due to the pump - and it's very difficult to keep things vaguely legal or safe while waiting for the engine to settle down to steady state conditions again. About the best I've got locally is Ngauranga gorge, where I can hold the throttle at a bit past halfway for long enough to get a reading. Full throttle just isn't happening under normal NZ conditions, although this tuning-on-highways method might work with a bike with 60 HP or less.

This said - it is working, albeit gradually. The bike was running better than ever last night - smooth, instant response, lots of get up and go according to the seat of the pants. No popping on overrun or high revving when returning to idle, either. Noise is starting to be controlled properly, too.

It's also becoming clear that the original airbox did actually help flow air at low RPMs. A long time back in this thread I'd calculated that resonant frequency of the airbox was around 2000 to 3000 RPM. The pod filters don't have that response, so I've lost a little of the initial pickup from the lights. The tradeoff is in how much more air the pods flow at mid to high RPMs. It's guesswork in the absence of a flowmeter or a dyno, but the AFR readings kind of tell the story... rich down low, lean to super lean up high. No wonder people talk about re-jetting when going to pods.

It's also clear that the bike does intake hot air from the engine at speeds below 50 k's. The mixture ratio drops a point or two sitting at the lights or rolling slow in traffic. That's not fixable in the absence of a cold air intake, but it shouldn't be a big deal once I get the slow jets I've ordered and re-tune the lower end of the throttle range.

[OddDuck]

The bike's done 1,500 miles since rebuild, odometer's now at 57,000 or so. I've spent the last few days of bad weather going through and doing a few checks and regular service.

The re-cut, re-lapped valves haven't moved. Clearances are still what they were on rebuild - mostly. The vertical exhaust opener was a little tight, at 0.003" to 0.004", so I took it off and papered 0.025mm off it to open the clearance up to the specified 0.004" to 0.005". Closer shims are a little loose but serviceable. I had to check the vertical inlet closer a few times before I decided to go with what was there, but it'll be up for replacement at the next interval.

One thing I ended up regretting was not having taken notes of exactly what shim sizes were used. Clearances are measured with a feeler gauge, but the shim lengths can only be measured with the shims removed from the engine. With cylinder heads still in place, this can get fiddly - the timing pulley has to be in the right place to allow the opener rocker arm to slide across and open up the valve stack. Having these measurements would allow the next size up and down shims to be pre-ordered before the next service. Unfortunately this thought only occurred once I'd got the motor back together again. It'll be worth doing next time around, even if all the shims are still OK.

Timing belts have loosened up a bit and had to be re-tensioned. They're in the last 3,000 miles of service life and will have to be changed at the next interval, at 60,000 miles. I used the 5mm (horizontal cylinder) and 6mm (vertical cylinder) allen key feeler gauge method again, erring on the side of slightly too loose.

The oil change wasn't a problem until the filter jammed. This engine's filter design has had me swearing on more than this occasion... the bloody thing is placed in a well in the crankcase. If the filter cup wrench isn't placed perfectly and slips, thus ruining the flats, there's no chance of getting a strap wrench onto the thing. Driving a screwdriver through the wall of the filter is possible but this didn't get it to loosen - I ended up just shearing the filter casing wall. In the end I had to take a plank of wood, mark out 8 holes plus center, and use self-tapping screws to fasten this to the oil filter's end. This got the bastard to loosen and it spun off from there.

The OEM workshop manual says to tighten the oil filter to 13 - 15 N.m. or so, while the oil filter itself says just 11 N.m. I must have tightened according to the manual, no wonder it bonded on too tight. I've had similar problems in the past with not using fresh engine oil to lubricate the filter's rubber seal ring. The original packing oil used isn't thick enough and if this fresh oil isn't used, the filter will bond into place good and tight even at 11 N.m. Dramas ensue.

One check I took was to pull the mesh screen (on inlet to the oil pump) and check what has been trapped there. This check should be done at every second oil change and definitely after doing engine work. There were a few light metal flakes - aluminium I think - and quite a bit of balled-up gunk which looked like fibres from gaskets or bits of loctite. The metal flakes are something I'm not sure about. They could be bits of plating off the new big-end bearings (that's a worry), loose bits of remaining swarf from the dremel work I did inside the casings to get snap rings out, or possibly the new crankshaft journal plug has unscrewed itself and is being shaved against the bearing, as the old one did. For now, there wasn't nearly enough to justify stripping the motor again to investigate. I'll check again at the 60,000 and see.

Winding the rear shock up a bit has worked, I haven't touched the exhaust pipes down since. The bike wallows a lot less in corners as well.

Exhaust headers had loosened, or possibly hadn't been tightened enough to start with. It's very easy to go sideways on these headers while tightening and I found it necessary to hold the header flange plate flat with one hand, tighten the first nut until the visual gap closed (but not actually tight on the flange), tighten the second nut in the same way, and then go from there.

I also swapped the AFR gauge sensor, from the vertical cylinder to the horizontal, to finally check differences in tuning between these.

Yep, they're different. It's not by much but the horizontal is running a point or two leaner at low throttle openings, balancing to about the same at mid throttle or higher. Both cylinders are still running far too rich at closed to 1/4 throttle. I'm still waiting on my slow jets (c'mon Amazon) and will have to continue tuning later.

[OddDuck]

I came back from the first ride post-service with oil coming out of the clutch cover drain. There have been a couple of clutch slips while riding, also neutral is getting hard to get into again, so apart it comes.

After pulling the springs, swashplate, stack, hub and then basket, to visually check all oil seals, it looks like the leak is through the tiny 12 x 8 x 3 shaft seal on the pushrod. Everything else checks out OK. The leak has been flung outward and hasn't contaminated the plate stack.

In a couple of ways it's a funny system... the pushrod, from the clutch actuator, crosses right from one side of the engine to the other. There's a couple of O-rings to seal it against gunk coming in from the chain's drive sprocket, then it's open to the engine's alternator and gear shaft compartments. These are splash-lubricated of course. Then the pushrod runs full length inside one of the gear shafts, with a roller bearing and then finally the shaft seal at the far end. There's only that one seal on the pushrod and it doesn't appear to have a spring-reinforced lip, it's purely rubber.

The pushrod came out soaked in engine oil (it used to be dry) so clearly it's being wetted from somewhere. Unfortunately I have no idea where or how this is happening. Maybe one of the gear shaft bearings was supposed to have an outboard seal, maybe the re-shimming of the selector drum is letting oil drip down onto the pushrod.. further investigation needed, but I'm not splitting the motor casings again if replacing the seal cures the problem. In the meantime I've tried applying a spot of high-temperature grease to the seal area as a temporary measure.

The clutch refusing to let go enough that neutral can be selected was a different issue. I took a good long look at the hub and the plates.

The hub's picking up some notching with use (this won't help). The plates were checked for flatness with the aluminium plate I'd used as a welding table, and surprise surprise, a few of them are warped. One at the base of the stack was warped quite badly. File this under 'should have been done the first time', I'd just looked and assumed it was good enough.

Any spring in the plate stack will affect the clutch releasing. The Oberon clutch slave has only 1.3mm of lift, and with 9 steels and 7 friction plates, it doesn't take much non-flatness per surface to keep clutch plates in contact. I didn't have replacements for the friction plates (they were OK anyway) but I did have an old pack of clutch steels which I'd saved.

Pressing the steels down onto the impromptu surface table, both ways around and rotated, pressing on one side, quickly showed if they were bowed or dished. I swapped plates around until I had a flat set, then set to with the needle files to chamfer the inner spline teeth so that they wouldn't cut into the hub splines and then jam up. This took a few hours work but I believe it's worth doing.

I also took the time to paper the swashplate, finding that in addition to clutch dust and corrosion, it wasn't flat as released by the factory. My guess is that it's held in a three-jaw fixture and lathed. The three jaws will distort it enough that a very slight three-lobed non-flatness will result. With the OEM clutch slave and it's high force / high lift, this isn't a problem. It is with the Oberon.

I tested as I went, reassembling the clutch stack and springs several times:

Flattening swashplate: slight improvement in clutch release
Replacing single, badly warped base steel: big improvement, roughly half of previous clutch drag
Going through stack and carefully selecting the best steels: best performance so far, near complete clutch release when lever pulled in.

Of course they may warp the first time I gun the bike at the lights, but I'll just have to try that and see.

[OddDuck]

The reassembled clutch is a joy to use. No issues when riding and gearchanges - including neutral at the lights - have never been easier.

Unfortunately I came back from the latest ride with a fresh problem. The horizontal cylinder exhaust header loosened enough that the bike started popping on overruns, and the exhaust beat itself could be clearly heard when the motor was cold. The interesting bit was monitoring the AFR gauge, since the sensor was in place on this cylinder when this happened.

AFR readings went from slightly lean to very lean - 16 / 17+ - in a very short space of time. As symptoms got worse, the indicated mixture got leaner and leaner.

Another ride, another day in the garage... I took fairings off and then removed the entire exhaust system. It became clear that the vertical cylinder gasket was barely making contact, and the horizontal cylinder gasket had been crushed on one side only. The sealing material between the gasket's metal faces was disintegrating and falling out, leaving the gasket as a squashed metal ring, with big air gaps. This was entirely my fault, I'd installed the exhaust headers skewed, and with the gaskets barely contacted - there wasn't the proper crush applied.

So why did this happen... I'd previously used plain BZP flange nuts to hold the exhaust headers onto the cylinder heads. This was vulnerable to the nuts loosening and falling off while new (that happened once) or rusting onto the studs permanently if the bike was ridden through a winter (that happened too). I finally got my act together and bought some of the proper Ducati flange nuts, which seem to be a very high-quality copper-bronze of some kind. They're pre-squashed so they're tight on the flange stud threads, and being an alloy they don't rust onto the studs. The problem with them is that the feel I'd had with spin-on, spin-off fasteners wasn't there, and that's what I'd been using to evaluate gasket crush before. I'd also been going very light on fastener torque, being worried about ripping threads right out of the nuts.

This time I took a few hours to have a play with refitting the headers, making sure that gaskets and flanges were aligned properly before tightening up. I did a lot of checks with verniers, finding that the exhaust ports, exhaust headers, flanges etc were all properly square as manufactured. This meant that a relatively simple check with a feeler gauge of some kind, between cylinder head and header flange, would ensure that the exhaust gasket was being crushed square instead of skewed.

In the end I found that positioning everything by hand, with finger-spun plain M8 flange nuts, and using a few Allen keys as the needed feeler gauges, worked. I had to run the nuts on the stud threads, with some CRC 5.56, a few times to clean the threads up first. There was no gasket crush applied at this point, this was just fitting everything to place and making sure it was all square. The system has to be assembled complete with the mufflers, since these affect the height of the header clamp joint at lower rear of the engine.

This done, the proper Ducati flange nuts were fitted and tightened in stages, keeping the flanges as square as possible during this. The manual specifies roughly 22 N.m. torque, but it's an old workshop manual and I wasn't sure that the nuts would take this amount of force. In end I went to roughly 16 N.m., tightening by hand and applying around 1 mm crush to the gaskets.

It's clear from the photos that neither cylinder had been sealed properly before. This will have affected tuning, so I'll have to re-check both cylinders.

[SVboy]

This thread keeps on giving. I admire your patience and problem solving ability. You have talked me out of ever owning a Ducati! I don't recall if you had your rear shock serviced when the bike was stripped? If not, why not? If so, if you set your sags for your weight f&r, the bike should handle better, rather than an exploratory " bit more preload" on the rear?

[Kickaha]

You have talked me out of ever owning a Ducati! ?

To be fair he is a OTT compared to most owners and the aircooled twins from that era are the easiest to live with

I should send him the 900 I have in the shed but I doubt I could afford the labour bill

[Voltaire]

To be fair he is a OTT compared to most owners and the aircooled twins from that era are the easiest to live with

I should send him the 900 I have in the shed but I doubt I could afford the labour bill

You have a rubber bandy one?

[OddDuck]

This thread keeps on giving. I admire your patience and problem solving ability. You have talked me out of ever owning a Ducati! I don't recall if you had your rear shock serviced when the bike was stripped? If not, why not? If so, if you set your sags for your weight f&r, the bike should handle better, rather than an exploratory " bit more preload" on the rear?

Rear shock hasn't been serviced yet. Two reasons: money got tight at the peak of the engine rebuild (I'm still clearing the credit card now) and suspension is something I'm still learning. My one track day made it quite clear that attention to suspension is needed if I'm on the brakes going in and on the throttle out of corners, but what I normally use the bike for is back country riding at a reasonable pace. For that, so far, it's been fine. You're right of course - correctly setting the suspension up is the next big thing to take on, but maybe that's best done next winter.

Ducati ownership:

Total strangers will stop what they're doing to cross the road and tell you "that's a beautiful bike mate". I've had people hanging out of car windows to hear the bike better.

Other bikers will confess envy (if they're young) or offer sympathy (if they've already been there).

Cops will take one look and assume outlaw riding is going on.

Garages / mechanics / dealerships will assume you are loaded with heavy and inconvenient bricks of spare cash.

Harley guys (OK, this did happen, but just the once) may have a sudden and terrible urge to take you on.

Your mother will worry about you. More than usual, anyway.

Spare parts are surprisingly available if you're from a Jappa background and home wrenching, although involved, is generally possible. You will do more maintenance than a Japanese bike, at least on a mid 90's. I can't speak for the newer generations.

The highs are awesome. The lows though... expect some mental things to go wrong. Frames that crack before 60,000 km's or engines that need rebuilds. Even the latest Panigales have wing mirrors that can snap off if the owner brushes past them the wrong way. Ducati doesn't do durability very well.

Beautiful to ride, though.

[SVboy]

The English journalist Rupert Paul bought an 03 SS iirc and then proceeded to make it better, esp in the suspension area. He wrote a series of articles in Performance Bikes a few years ago. Would be worth looking up perhaps?

[AllanB]

Even the latest Panigales have wing mirrors that can snap off if the owner brushes past them the wrong way. Ducati doesn't do durability very well.

Beautiful to ride, though.

Meh - Yamahas have gearboxes that need recalling, Suzuki have sub-frames that break, there are Triumphs that burnt shit loads of oil, Aprilia V4 recalls etc etc.

Ducati pulled finger on quality some years back, and needed to. Service intervals keep getting push out - belts and valve clearances on mine are at 24,000 - the latest engines are 30k. Japanese engineering figures. Mind you the book does not say how many 24-30k services you get! Time will tell.

They are still all assembled by hand I read recently - I don't know if that is actually a good thing! It may explain some of the little quirky things.

Quirky things - that people call 'character' but if it was a Jap bike they would bitch about them. How's that?

Writing this I can't recall reading about or hearing about any real issues with a specific model, engine or 'part' on a Harley - well other than the owner and their issues. I must be wrong.

[OddDuck]

To be fair he is a OTT compared to most owners and the aircooled twins from that era are the easiest to live with

I should send him the 900 I have in the shed but I doubt I could afford the labour bill

Why thankyou, but I'm not a pro by any means. Just trying to get my bike running properly. I post in detail because maybe this stuff will be useful for someone else out there driving a spanner, also writing up helps me to sort my thoughts out and remember what I've been doing.

[Kickaha]

You have a rubber bandy one?
It belongs to my brother, needs revinning

[OddDuck]

Just back last night from a 900 mile, 3-day trip. No issues with the bike aside from a front tyre nearing the end of its life and going a bit triangular.

It's time to do a few courses and also a couple more track days. Skills are going rusty and in some areas are slipping backwards. I caught myself projecting over the centerline on right hand turns quite a bit, also failing to lean more if a corner tightened up.

That last one - failing to lean more - is a nasty legacy from my first bike, a POS Honda Wet Dream with ancient rock hard tyres. They'd walk sideways even in the dry and in the wet the bike would skid like hell. The tread was just above the legal minimum for the WOF but always made it... and never seemed to wear down. I thought this was normal and never changed the rubber. Oops. Absolute first thing I should have done, along with going to a track and seeing just how far the bike can lean and what it's like to ride banked over.

The trip's been great. I went up with a mate, we went looking for back roads and twisties, and generally stayed off the arterial routes. It worked. Very low levels of idiot driving seen, very high levels of everyone getting along instead. One feature of the back roads, and out of the way places to pull up and have a bite to eat or a coffee / pint, has been how approachable people are. Directions, information, or just having a laugh - there's been quite a bit of that.

It was a big quadrangle across the lower North Island - Lower Hutt, Pahiatua, Ohakune, Whanganui, back through Pahiatua again and not too many bits repeated. I'll stay away from a detailed route description, it wasn't that kind of trip anyway. We'd get the maps out when we'd stopped and just go looking for the next bit of something we hadn't ridden yet. If it was off a main road, not gravel, and going roughly the right way then that was what we'd do. This turned into a fast way to find a lot of really good roads to ride, with the occasional patch of gravel or single lane country road to deal with.

There was a change of plans. Originally we were going to take two days and split up in Whanganui. I'd either go further north or just head home. We got to Whanganui about 6 and we were both getting pretty tired. I listened to his advice and dumped the schedule, adding an extra night to the trip and carrying on in the morning. Good call, both for fun and safety.

Full thermal kit got used on the first day and it was needed. It got bloody cold around Waiouru, especially after dark. No rain though.

Near misses: I had a small group of sheep run out in front of me once and some idiot failed to give way properly at a roundabout in Whanganui, no contact on either occasion. That was it. Fantastic trip all round, home very tired but safe and happy, today is going to be about recovering instead of riding more. Time to go wash the bike and read the paper.

[ruaphu]

Yep love those kind of trips, no real plan, just a general direction and an occasional consult of the map to see 'where else' can be ridden out of the usual routes. Makes for interesting days at times. Good to hear the bike is running well and the comments on skills. Take care eh. Btw, great thread, enjoyed every entry.


Sent from my iPhone using Tapatalk

[AllanB]

The tread was just above the legal minimum for the WOF but always made it... and never seemed to wear down. I thought this was normal and never changed the rubber. Oops.


Hear ya. I had a Kawasaki for years - had done minimum kms on it at one stage for a year or so and had parked it up over winter. I got it out for the summer, handled odd - not as I remembered.

I went through everything - new wheel bearings, checked, greased and reset steering head bearings, changed fork oil. Checked wheel alignment. Pissed around with tyre pressures. Told the shop about it as they new the bike well - I purchased it off them new. The owner asked about tyres - heaps of tread, good shape, great brand. How old? Hmmm checked my log book - can't recall how old - maybe 4 years. We did the old fingernail check - hard. Very hard. New rubber and it was back to normal. He reckons they went 'off' due to low use, age and sitting over the winter period.

[OddDuck]

Interesting that it went from OK to off just over winter. I know they die from old age but that seems like a very short time of not using it for the rubber to go hard.

This current tyre wasn't used for nearly six months but it was still OK when returned to service. It did wear out though. Old rubber rooted, replace with new... S20 Evo gives way to new S21.

The photos are shot from the front. I tried to show a hollow on the right flank of the worn-out tyre; when cornering right, it felt like there was a very abrupt weight transfer toward the edge of the tyre. The bike would change what it was doing quite dramatically with just a few degrees more lean angle. It got downright scary in a few corners toward the end of the day.

One thing about the Evo's was that once they started wearing, they'd go fast... this tyre went from tread and wear bars to as-pictured in just three days of high mileage riding. That said, I didn't think it owed me anything more. I'd got 7,500 miles out of it, not bad for such a high performance tyre.

Doing a spot of light maintenance while changing the wheel, cleaning and re-oiling the fork tubes... one thing about USD forks is that brake dust will collect on the slider legs. The dust seems to lift oil but retain water, or do something similarly corrosive. I'd found the beginnings of rust spots forming through the chrome about two years ago. This is bad news because if the fork is bottomed out, the sharp-edged rust can cut the fork seal lips and cause an oil leak.

The rough fix was to very carefully blend the rust spot's sharp edges with the finest wet'n'dry I could find, 2000-grit I think. Obviously the mirror chrome finish in that area is ruined, but it works for now. The only real fix is to have the legs ground and re-chromed. It's not worth that sort of expense for these forks, they're the cheap non-adjustables of the Ducati range. In the meantime, keeping it clean and protected with a layer of rag-applied fork oil is working to keep the rust spots stable.

The last thing I did was have a go with a different technique of chain cleaning. I wanted a method that was reasonably quick, cheap and easy, since (according to the box for the DID chain) it's supposed to be cleaned and lubed every 500 km's if I want to get the maximum life out of it. 500 k's isn't going to happen, but every thou or so would be nice.

How to clean your chain... cue massive debate. Everyone's got their own method. I used to use a very involved procedure with water based degreaser, low pressure hosing and the like, but it's a marathon. Time to go simple, fast and effective.

Kerosene in an old tin (the DID box specified this as the preferred cleaning agent), paintbrush, rag, nitrile gloves, and the left muffler removed for access, and I had a clean chain in about twenty minutes. Rags can be had out of the better auto tool shops (like Twigg's) for about $45 / 10 kgs or so. Engine was left off of course, rear wheel or chain turned strictly by hand.

Leave the engine off. Really. The world's got quite a few bikers and ex-bikers in it who've lost bits off fingers and thumbs - or worse - while taking the easy route of running the engine in order to pull the chain through the rag. That rear sprocket loves to suck things in. It's only bloody obvious after it happens... don't let it take your hand.

That done, I re-lubed the chain (without a quick fang to the shops and back to shake the kero off first, which should be done next time), then geared up and took the new tyre out for a proving ride.

Awesome. I'd rated the S20 Evo the best tyre I'd ever ridden (admittedly limited experience), the S21 is just as good or even better. The bike is utterly planted and in control, it does exactly what it's told to do.

[SVboy]

I use a similar chain cleaning method, except I finish off by washing the chain using a hose, then ride the bike to dry the chain and get some heat in it. Then I use chain wax and let it penetrate and dry over night. I love the S21s. Bridgestones best tyre so far?

[OddDuck]

I can't speak for the rest of Bridgestone's offerings but the S21's are fantastic alright. Unfortunately I think I've got a slow leak in the front tyre or valve. I'd found it at around half inflation the other day and will have to be checking pressure every couple of days for a while. I've no idea if there's a fix for this yet, or if the problem will settle down.

I've been tuning the carburettors again. Just a couple of practical notes, for anyone else doing this... very often the carbs are positioned so that it's difficult or impossible to get standard tools in. Sometimes even jeweller's screwdrivers won't fit. The safe option is to pull the carbs off the bike completely so that you've got control and can see what you're doing. Petrol everywhere of course.

Then it has to be done again, and again... Bit of a hassle, then I remembered something and got the mountain bike multi-tool out. I took the tool to bits on the bench and got the flat-blade screwdriver out on its own. This was nearly perfect for working on jets, screws etc in situ, because it was the right size and shape, and the P-end gives enough of a handle to work with as well as good position control. A while ago I'd bought some hex-ended drivers for this type of work, the kind of bits intended for a drill driver, and they work for the fuel mixture screw but aren't long enough to get at the slow fuel jet.

The paintbrush is useful for getting accumulated dirt and grit off, before taking inlet trumpets or float bowls off. Gotta stop dirt falling into jets, wedging seam lines open, or similar. I've found that synthetic bristles will be the right combination of stiff / flexible for the job, they'll go into corners and so on, but they'll loosen dirt up nicely. Stuff rags into carb throats first of course, it's amazing how dirt can move around during this job.

The sensor for the AFR gauge had been mounted on the header pipe off the horizontal cylinder. That means that it's under the engine and in the firing line for gravel off the front tyre. Dents on the sensor housing are visible in the photo. The manual warns that the sensor is vulnerable to shock and shouldn't be dropped or subjected to vibration, so this is obviously not good for it.

It's obvious in hindsight, of course... the underside of the fairing has been ripped to shreds. I just hadn't expected to see this so soon.

Now this is pure speculation... I don't think the front wheel spits bits of gravel out at high speed. I think that what happens is that it pulls gravel upwards as the wheel passes over, either by the rubber sticking, or suction. The gravel then goes straight up relative to the ground and encounters the bike, at whatever speed the bike was doing. If that's (ahem) 100 k's, well, that's probably going to chip the paint.

Anyway, I'd found out what I needed to know: there is a difference in mixtures between the two cylinders, but it's slight. The horizontal cylinder runs about 1 point leaner than the vertical cylinder. Given how much the mixture ratio can vary, it's not usually that big a deal except near closed throttle. I'll check the horizontal cylinder readings again once I've got more tuning done, in the meantime the sensor is going to the vertical cylinder header again, safely tucked behind the engine.

[OddDuck]

And here's notes about the carburettor tuning itself... the slow jet kit arrived earlier in the week. It's not Keihin genuine, this was a pattern part set made by A-Bax Engineering and distributed by EBC Brakes, via Amazon. I've been wanting these for a very long time. An ongoing problem has been an over-rich condition in the vertical cylinder, leading to carbon fouling of the plug, piston crown, head, ports... I've done everything possible with the mixture adjustment screw and slow air jet screw, but there's no getting around the jet size.

So, I changed these slow jets from 60 to 52 (horizontal) and 50 (vertical), used the AFR gauge to get the bike running with a ratio of around 13 in each cylinder, went out on a ride and promptly had problems with lean running at 1/4 and mid throttle. I didn't manage to get to full throttle but it became very clear that there was a lean problem. I also encountered serious problems with starting the engine, both first thing in the morning and after the bike had been sitting outside for a few hours.

This led to a session with this excellent guide (shame the charts don't seem to come up):

http://www.factorypro.com/tech/tech_tuning_procedures/tuning_FCR_Burns,Pat.html

My method for learning this stuff has been:

Read a bit
Do a little work
See how it goes
Find the problems
Read a bit more and repeat

It's iterative and hard work sometimes but there's just no learning it all in one go. This time I've finally appreciated how important the slow air jet screw really is. This single screw covers a jet range of 45 to 155. As Pat Burns points out (and as I think I've just found out for myself) this also affects mixture quite markedly at high revs and moderate throttle openings, as encountered cruising the highways and back roads. I'd been running with the screw 1.5 turns out, equivalent to a jet size of 125.

The bike's also, quite persistently, been running rich at low throttle but increasingly lean as the throttle opens up. I'd been thinking for some time that I had the wrong needle taper, but changing the slow fuel jets really highlighted this behaviour. If the slow air screw is the main reason that it's been rich down low but lean up high, it's a lot easier and cheaper to have a play with this before getting into changing needles around.

Further reading also showed that it's quite naive to tune for a constant AFR reading. I'd been aiming for 13 to 14 throughout the throttle range... it's not that simple. The engine will have a sweet spot for mixture tuning at each throttle setting. Near closed throttle, this sweet spot is best found by ear, not by AFR reading. The technique is to idle the engine (once warmed up), blip the throttle, and see how it settles to idle again. If it hangs at high revs before settling, it's running lean. If it drops below idle speed and then comes up, it's running rich. So far it looks like the engine quite likes to run at 11-12 AFR near idle.

Anyway, I left the 50 / 52 jets in place and tried some work with the slow air jet screw and idle mixture adjustment screws. Interim carburettor settings are now:

Slow Fuel Jet: 50 (vertical), 52 (horizontal)
Idle Mixture adjustment screw: 2 turns out, both
Slow Air Jet Screw: 1 turn out, equivalent to 100 jet
Needle position: 6th from top (I still don't know what needle I'm using; there are a whole family of these, with 3 letters stamped on the needle somewhere)
Main Jet: 220 (both)

and of course I'm using the pod filters, which dramatically change how the engine breathes, and which is why I got into all of this in the first place.

[OddDuck]

In the previous post I'd mentioned issues when starting. THe Keihin FCR41's don't have a choke. Voltaire has mentioned starting difficulties with his FCR39's.

A memory that stays with me is being on the road with a mate and trying to get going, first thing in the morning. It had been a cold night, the bike was stone cold, and I had to crank the hell out of it to get it to catch. Then it was gutless for at least five minutes, until it warmed up. In the meantime he zoomed off, while I was desperately trying to not lose him in a strange town, with no arranged meeting point, and the bike stalling every time I tried to open the throttle up... Very frustrating.

There have been times in the middle of winter when it wouldn't fire at all. Crank the hell out of the motor, listen to it fail to catch, get really pissed off with it, keep on trying but the motor just won't fire up. It was certainly a pig to start when I'd been trying to get AFR ratios of 13-14 at idle, I really struggled first thing in the morning when trying to get to work.

Following last night's efforts with the slow air jet screws, that problem has gone away. It's catching, from cold, at the first stab of the starter button. I haven't yet checked the plugs for fouling (AFR tells me I'm running 11-12 near idle, lower than 11 closed throttle), but the motor seems to be happy enough. It might be a very different story when I can get out on the road properly, but there's definitely something to this business of tuning the motor by ear in the lowest 8th of the throttle range.

It got me interested, though. Why would a petrol engine have trouble starting, and what fixes can be applied?

I did my reading, or tried to. There's very little public information about the technicalities of a cold engine start (sometimes I like to nerd out with thermodynamic theory and calculation; no luck this time). About the most that I found was of course 'the choke', deliberately restricting inlet air flow to force a richer mixture so that the engine would start.

It's a pretty old-school solution. It guzzles fuel, it pollutes like hell, and I'm pretty sure it helps to coke up engines or wash piston rings down. But it's cheap, it's easy to put in place, and it works. That's about as far as that's got, with petrol engines anyway.

Then I stumbled across what happens with diesels. Apologies to those of you already in the know, this was quite something to me since I'm from a petrol background.

It turns out that cold starts are a massive problem for diesels, particularly those engines intended for winter / mountain / arctic conditions. Diesels depend entirely on heat of compression for their ignition. If you take a cylinder of air and squash it, hard and fast so it doesn't lose heat, it'll cause oil squirted into it to spontaneously catch fire. No spark needed. This falls down if the engine's cold enough and the intake air is cold too. The heat of compression is lost to the engine and fuel injected into the cylinder won't do anything, since it doesn't ignite.

The engine would heat up in a hurry if it could catch... but until it's compressed enough air enough times that the cylinder has warmed up, it won't fire at all. You could be cranking that starter for a half an hour, and if it's losing heat at a fast enough rate (like in a blizzard, for example) you might never get there at all.

I'm fairly sure that similar happens in petrol engines. When the spark fires, there's a tiny bubble of burning vapour. It's got an internal volume and a surface area. The internal volume carries its heat, the surface area radiates that heat outward. Spheres have tiny internal volumes relative to surface area when they're small. If the surroundings are cold enough, they'll quench that bubble of combustion before it has a chance to expand.

We're all familiar with that burp-burp-burp sound of an engine being turned over, sparking, but not quite catching.. this might be what's going on in that situation. People talk about three things being needed to make an engine fire: fuel, air, spark. I think that during starting we need to include heat as well, the old fire triangle coming into play here.

Among other solutions, diesels use air pre-warmers. They deliberately heat up the incoming air. These tend to be very robustly made heater elements mounted inside a flange, for fitting somewhere in the intake system. The heater elements are made for good thermal connection to the airflow, while not impeding it. A figure I remember for power was a 2.7 kW heater (!) for use with an 8 litre engine, so it looks like they take this stuff quite seriously.

This got me curious, so I had a look at power requirements for air pre-warming for my engine, assuming normal (unassisted) starting would work down to about 10 C, and starter motor cranking speed for my engine was around half idle, say 450 RPM.

There's a useful power source for heater elements already fitted to the bike: Oxford Hot Grips. I checked output voltage and it's 12V, pulse width modulated (25%, 50%, 75%, 100%) depending on setting. The grips are around 7 ohms each.

That means there are two heaters, of 20 watts capability, already on the bike. It's obviously not going to work to try to use the grips to pre-heat incoming air, I'd have to fabricate a custom heater element around the intakes and switch power to it... but what does 2 x 20 watts do, in terms of pre-heating air while cold cranking?

Without going into detail in the calculations, it works out at something like 6 degrees C of warming inlet air up. There's enough power while cranking to do this without affecting the starter motor or ignition, just turn the lights off.

Experience with the bike (OK, with original carburettor tuning) was that it was fine to cold start down to about 12 degrees. Below that, quite abruptly, it became a real mission to get the motor to catch. 6 degrees pre-warm doesn't sound like much, but it might be just enough to make the difference on a winter morning.

I gave this idea a go with a hot air gun and indicated inlet surroundings temperature of 40 C. It seemed to work, but conditions were cool, not cold, and at this time I can't remember if this was with the carburettors tuned lean idle or not. It's a crappy proof of concept, the real test is one of those mornings when breath can be seen on the air, but we haven't had a morning cold enough lately.

In a pinch, on the road, this could be done on tour. Hot air gun, extension cord, power socket from the motel room. I'm not sure I'd want people seeing me do this, though.

[swbarnett]

Interesting. It explains something that I really hadn't thought much about for the past few decades. My wife and I used to have problems with our CB250s on cold mornings back in the '80s (when there were cold mornings). They just wouldn't start until we threw a bucket of hot water on the engine block. After that they would start first crank.

[Ocean1]

My 525 has been hard to start forever, especially on semi-stale fuel. And yet once warm it's fine.

Sticking a 2Kw fan heater under it for 5 minutes works very well.

[OddDuck]

The past couple of weeks has been:

- first attempt to fabricate an induction pre-heater, for starting
- more carbie tuning.

I'd re-read Pat Burns excellent FCR tuning guide and finally noticed this paragraph (important bit in bold):

Main air jet:

If you find that the engine runs perfectly at WOT near the torque peak, but becomes lean toward redline, select smaller main air jets. Conversely, if the engine runs perfectly near the torque peak but richens toward redline, select larger main air jets. Changes in air jets may require changing the main fuel jet. Say you have good performance at engine speeds leading to the torque peak under wide open throttle with a 150 main fuel jet and 200 main air jet. Should you need to richen the mixture at full revs and full throttle and select a 180 main air jet, you may need to go down to a 145 or 140 main fuel jet to keep the lower rpm mixture the same as with the 150/200 combination. Generally (there are always exceptions), once the main air jets are properly selected for the intended application, they need not be changed again unless you change the intake restriction (modify the airbox or use different filter) or change engine or exhaust specification. Varying atmospheric conditions can usually be dealt with by fuel jet, fuel screw, and needle changes.

Now why didn't I notice that the first dozen times I read this guide. I have definitely modified the airbox: it's been changed for K&N RU1750 pod filters.

I've been battling rich down low, lean up high pretty well forever. Maybe this was what was going on, instead of it being the needle taper I'd been obsessing over. I went and found an NZ supplier for the main air jet (thank you Motozone) and promptly ordered a few sizes down from the 200's fitted to the FCRs as supplied. Tuning runs followed. Listen to motor first, check AFR gauge second.

Conditional success. I now have a bike running OK through the useful riding range. Although I'm sure there's room for further improvement, here's current tuning, for anyone else podding a 900SS with FCR's:

Needle: EMT
Clip Position: 6th from top
Pilot Jets: 52 (horizontal), 50 (vertical)
Idle Fuel Screw: 1 turn out (both)
Slow Air Screw Jet: 1 turn out (both)
Main Air Jet: 148 (down from 200)
Main Fuel Jet: 220 (although this is wide open to review)

There's one very important factor in this tuning: adding to the insulation I'd placed on the intake stub pipes.

These dinky little intake manifolds have a huge effect on mixture strength, how the engine runs, exhaust noise etc due to what temperature they happen to be at. In their as supplied state, they basically aren't insulated from the cylinder heads. They get hot. They get stinking hot, in fact... touch them to check how hot they are and you're courting burns.

As they get hot, they heat up incoming air. This reduces air density. A fuel-air mixture will need less fuel to have the same AFR ratio. However when you're starting that motor, everything's cold. You'll need a richer mixture to get the same AFR ratio, let alone something rich enough to start a cold motor. A carburettor obviously doesn't compensate for this temperature variation, so tuning the carbies for closed throttle operation has always been a tradeoff between running ridiculously rich while tootling around town, or the bike not starting at all on a cold morning.

Right... what if they didn't get that hot while running? Wouldn't this reduce that tradeoff in carb tuning?

I'd been to some trouble to insulate the stud bolts, the major conduction path. It reduced the problem greatly but didn't quite eliminate it. With this in mind, I did something I've been meaning to do for a while: making the paper gasket between head and pipe a bit thicker. The OEM Ducati gasket is all of 0.4mm thick. I bought a 500 x 500 piece of 0.5mm gasket paper - good stuff, PTFE-coated, German made, rated to 200 C - and cut an extra couple of gaskets for each inlet, effectively doubling or tripling the heat resistance.

The gasket paper itself deserves a mention. Repco, Super Cheap Auto etc are the obvious places... all they've got is Flexovit. It's not coated and (as I'd found out for myself) it crushes over time, petrol exposure, and under heat. It's simply not up to the job. The paper I'd bought was three times the price I'd paid for the Flexovit and about ten times the quality... go to an industrial seals supplier (I used Seal Imports) and have a chat with the bloke about what you're doing, go in cashed up and try not to wince when you hear the price.

The OEM head studs also weren't long enough. Replacement involved purchasing what I could find and cutting the cylinder head threads a bit deeper into the plain portion of the stud.

Threadcutting: die nut. Holding the stud, without munting the threads in the vise, involved taking a pair of perfectly good plain M8 nuts and putting a hacksaw through one flank, turning them into threaded 'C's. This meant they'd crush in the vise, clamping stud threads with a mating threaded surface, and thus gripping the stud without damaging it. It turned out to work brilliantly for filing / hacksawing, threadcutting turned the stud in the nuts until it stopped and then it'd cut... but it still worked.

Anyway... the insulating bushes on the mounting studs were a good start, the thicker gasket paper has got me the rest of the way. The inlets are now only just a bit warmer than ambient, even if the bike has been running for a while. I might have to thin them down again for winter but for now they're working just fine.

As to pre-heating, to aid cold starting... no pictures for this as yet. I'd had the idea of constructing a wire heater element, mounted immediately around the outside of the pod filters, and had gone shopping. The design was a fibreglass plate top and bottom of the pods, with Nichrome heater wire strung back and forth between them. There'd be many passes, to cover as much pod surface area as possible, and several elements in parallel, to balance electrical loads vs wire resistance.

Then I realised, before building it, that it's just not a good design. It's fragile, it's clunky, and the wire is a very real fire hazard. Aside from anything else, the wire is going to be shaken mercilessly by engine vibration and turbulence from intake air. It'll break by fatigue early and often. Nope. I need something that'll last. Then I realised, I already know that inlet air is heated by hot inlet manifolds. The heater element doesn't have to be in intimate contact with inlet air; it just has to warm up something else that already is.

The current plan is to go shopping for a pair of band-clamp heater elements, designed to fit onto piping, and fit these to the outside of the inlet stub pipes. I have no idea yet if anything's available in 12V / 38 mm. In theory it's got a lot of advantages: I can use the thermal mass of the inlet pipes to store energy, the heater itself can be robust and MIMS (Mineral Insulated, Metal Sheathed), and it's ultimately just a bolt-on modification, not something fabricated. I can also use safeties like bimetallic switches against overheating. Right, further browsing / shopping / building to do.

[pete376403]

For inlet air heaters - how about looking at diesel engine glow plugs : 12volt, robust, probably screw into something so easy enough to mount. Find some up at pick-a-part. For your application they only need to operate under cold start conditions, right?

[AllanB]

Is there a special set of screw drivers or something Ducati mechanics use for carb tuning? Bet they don't remove them in the shop.

[OddDuck]

For inlet air heaters - how about looking at diesel engine glow plugs : 12volt, robust, probably screw into something so easy enough to mount. Find some up at pick-a-part. For your application they only need to operate under cold start conditions, right?

Apologies for the delay in replying, been doing a lot of study and thinking... I had a look at this and the glow plugs are only a good idea if they're heating the inlet stub pipe from the outside. They really do glow, we're talking 800 C plus. I'd have to fabricate a clamp-on, blind bracket of some kind and rely on bulk heat conduction through metal, with fuel-air mix kept away from direct contact.

The glow plug relays that go with them are seriously interesting, though. These are exactly what I need. Timeable from 2 to 30 seconds, able to handle high current, and cheap as chips (out of pick-a-part anyway).

Alternatives. I'd looked at band (nozzle) heaters, there's a page of them here: http://nz.rs-online.com/web/c/automation-control-gear/temperature-control-process-heating/band-heaters/?sra=p

Unfortunately the inlet stub pipes have a flange at one end, then a curve and a rubber boot on the other. The only bands able to get over the boot and around the curve are too long to fit on the straight length available on the pipe. This is the thing about this kind of work - one detail that doesn't match up and that's it, no can do. Then I remembered something from work and realised that these things could work:

http://nz.rs-online.com/web/p/silicone-heater-mats/0245528/

These should go on reasonably easy, I can wrap around with some thin stainless on top and hose clamps to secure the assembly. No fabrication needed. They're only 5 watts but since the inlet pipes can store a reasonable amount of heat, it's worth a go.

[OddDuck]

Is there a special set of screw drivers or something Ducati mechanics use for carb tuning? Bet they don't remove them in the shop.

Didn't see a set of these in my workshop manual... in the meantime this works:
328518

The smaller screwdriver to the side is the hex driver bit that fits into the air-fuel mix adjustment screw. Doesn't quite reach the pilot jets though.

[OddDuck]

Voltaire, might have something for you... starting.

I'd been on a road trip over the weekend with a mate and had real issues starting from cold, first thing in the morning. It was a little nippy, nothing serious, but I really had to crank the hell out of the bike to persuade it to catch. Lots of cranking the throttle to squirt some petrol to richen it up, lots of backfires in the motel parking lot first thing in the morning, etc etc...

Anyway, I'm at the 60,000 mile service now and as part of that I've changed the plugs, finally.

Guess what, it fired up on the first crank. It caught literally the first time the motor turned over, first revolution, that kind of thing. There were no tricks with cranking the throttle to give it a squirt or two of petrol first.

I'll still have a play with pre-heaters for starting but for now it looks like carbon deposits on the plug insulator are a lot more important than I'd thought. The old plugs are badly blackened but still starting and running. They're not dead but it's now clear that they were walking wounded.

I'd been running 9's, might have been running a grade too cool. Carbon will deposit on the plug insulator at running temperatures below 450 C and needs temperatures between 450-ish to 800 C to burn off again. I've switched to 8's, as NGK recommend, and will have to see what this does to tuning.

I strongly suspect that this changes a lot. I should have been tuning with clean plugs from the word go.

[Voltaire]

My 900 came fitted with a Yoshimura digital readout that gives air temp, air temp off a sensor and voltage...oh and being Japanese a clock.
My 900 will only really 'catch' when the sensor reaches 25+ degrees ( its mounted on the engine somewhere), thats after numerous attempts listening to the life of the sprag clutch diminishing on each press of the starter.
I concluded that the loooooong manifolds need to heat up as the vapour is probably turning back into liquid from condensing on the manifold.

The FCR's might give a bit more ommph and sound nice when you crack them open but I scored a set of rebuilt stock carbs with all the cables and throttle.

Doing the conversion now and the FCR's are in a box to give to the next owner as shelf bling.
I've spent weeks and endless test rides getting my Guzzi lemans 2 running right and am some what over fiddling with carbs.

Conclusion- chokes are useful.

[OddDuck]

I've spent weeks and endless test rides getting my Guzzi lemans 2 running right and am some what over fiddling with carbs.

Yep I hear ya!!

[Voltaire]

Yep I hear ya!!

On the lemans one cylinder was running lean, other rich, both had same jetting and settings.
Once a plug fouled that was it for the plug.
Eventually swapped the carbs over for a test and fault went with carb....one of the Eureka moments.
My mate said stick it on Trade Me but I did not want to see it under optimistic sellers:killingm

To my eye the carbs looked fine, did more research ( trawling internet)
In my Dellorto bits box found some similar sized main jet, emulsion tube,needle and tried this.
Much better, took longer to foul plug on same 30 km run.
Ordered gasket and seal kit, new needles, emulsion tube ( needle jet tube) and idle jet.
Did a 200 km run on Sunday and runs perfectly.
900 is under a blanket waiting for the stock airbox to arrive.

I did change the plugs on the 900ss, I was heading down the route of getting rid of the crap stock ignition and fitting an Ignitech but the rebuilt stock carbs came up on TM at a good price.

[Kickaha]

The current plan is to go shopping for a pair of band-clamp heater elements, designed to fit onto piping, and fit these to the outside of the inlet stub pipes. I have no idea yet if anything's available in 12V / 38 mm. In theory it's got a lot of advantages: I can use the thermal mass of the inlet pipes to store energy, the heater itself can be robust and MIMS (Mineral Insulated, Metal Sheathed), and it's ultimately just a bolt-on modification, not something fabricated. I can also use safeties like bimetallic switches against overheating. Right, further browsing / shopping / building to do.


What about wrap on handlebar heater elements, probably not quite big enough in diameter though http://www.aerostich.com/aerostich-warm-wrap-grips.html

How hot do they need to get and how quickly?

[Grumph]

The electrical contractor I once worked for had on the shelf Element Tapes. Came in various lengths and widths, looked like a woven cotton tape with a metallic thread through it. Two wires coming out one end. I asked about it and was told it was for DC applications.
I never had a use for it, so it stayed on the shelf...Business has changed hands but it's probably still in stock.

[OddDuck]

What about wrap on handlebar heater elements, probably not quite big enough in diameter though http://www.aerostich.com/aerostich-warm-wrap-grips.html

How hot do they need to get and how quickly?

Thanks for that. Interesting that there are under-grip heaters available - I'd never heard of them before but it makes sense that they're out there.

I had another look at the inlet stubs the other night and the straight length available for wrapping a heater is very short - only around 45 - 50 mm. The pipes themselves are 150mm-ish but a lot of that gets taken up with the rubber boot/insulator/seal for the carburettor, the flange, the vacuum gauge fitting and the curved neck.

So far the winners are the stick-on silicone heaters from RS, mostly because they'll go straight on. They're cheap enough - $40 each - and it's a spot of work cutting some stainless shim for backing plates, but that's all that's needed to fit them.

As to how hot they'll need to get... it's a bit of try and see for this. I honestly won't know until I give it a shot. 5 watts isn't much but if the stubs are warmed up before I turn the motor over, I can store the 5 W being pumped in and raise the temperature to whatever is needed.

[OddDuck]

The electrical contractor I once worked for had on the shelf Element Tapes. Came in various lengths and widths, looked like a woven cotton tape with a metallic thread through it. Two wires coming out one end. I asked about it and was told it was for DC applications.
I never had a use for it, so it stayed on the shelf...Business has changed hands but it's probably still in stock.

I had a quick look last night and there's quite a bit available. Most of it's mains powered, for underfloor heating or similar, but there are some DC versions around. The stuff I was seeing is called Trace Heating Cable, RS have a lot, there a lot of insulation / heating companies with it, and Omega Engineering in the US have a lot of it too.

The trouble is fit. As I'd replied to Kickaha above, the area available for fitting a heater is restricted (unless I machine up a collar or something) and it really limits what can be placed. There's also heat, vibration, petrol resistance... whatever is built will have to be clamped and secured very carefully against vibration because otherwise the heater elements will either snap or will chew their way out of the insulation.

[Voltaire]

The electrical contractor I once worked for had on the shelf Element Tapes. Came in various lengths and widths, looked like a woven cotton tape with a metallic thread through it. Two wires coming out one end. I asked about it and was told it was for DC applications.
I never had a use for it, so it stayed on the shelf...Business has changed hands but it's probably still in stock.

Its called Trace Heating, when I worked in the UK it was wrapped around pipes to stop them freezing.

Air cooled VW's had an exhaust heated inlet manifold to assist cold running.

I think the Ducati inlet manifold to the front cylinder is just too long for cold starting with carbs without chokes.

[OddDuck]

Heaters on order, in the meantime I finally got onto an issue that's been waiting for a while.

The rear brake caliper is positioned vertically above the axle. This means that the brake pads are hanging from their retaining pin - their weight isn't carried by the caliper in any other way. Vibration plus abrasive brake dust means that they've been cutting grooves into the retaining pin, also the pin itself has been cutting its way downward in the caliper body, ovalling the pin's hole.

I got the verniers onto various components. There's a pair of half millimeter cuts in the retaining pin, a matching half mill in each pad's tongue, and nearly a mill in the caliper body itself.

This means that the pads are slowly but steadily working their way downwards. Fresh area on the brake disc is being brought into play, it isn't the same thickness as earlier metal, and now the pads are only engaging on their edges. The brakes themselves have become spongy due to spring / flex in the pads, as the gap in the middle is taken up. This would all settle down if I used the rear brake a bit more of course.

I'm not wild about replacing an otherwise perfectly good caliper because of one ovalled pair of holes. What to do...

First: stop the pin flapping around loose in the caliper body. Second: take up the vertical slack between pads and pin. It'd be nice to include something with some shock absorbing qualities in this modification, if possible.

Thin-walled heatshrink onto the pin, and running a drill through the ovalled caliper holes to round them again, got the pin located with a light sliding fit. A drilled-out piece of stainless steel tubing then fitted over the pin and held the pads, after their tongues were filed out very slightly. Having a drill set stepped in 0.1mm increments was very helpful for this, I also needed something to chamfer the tube inner edges post drilling so that it didn't carve the heatshrink up when fitting.

There is a catch - the pads have to sit cleanly against the inner walls of the caliper when braking, as designed. They can't load up the retaining pin via their tongues, otherwise the pin will bend. There has to be fore-and-aft movement possible between the pin (or its cover tube) and the pad tongues. I'll have to check this properly in the morning, but it's not a big deal to pull the pad stack out from the caliper and file a bit more if needed.

This is only an issue on high-mileage bikes. I'm nearly at 60,000 miles and it's only really started becoming a problem in the last few months. It's also only a problem on the older bikes. I think that Ducati have revised the design: the newer retaining pins feature spring collars, so they're located in their calipers without being able to bounce around in the holes. The pads will still notch the pins, but it's not a big deal to replace these when needed.

[OddDuck]

I ordered the stick-on 5W heaters from RS and tried fitting them.

Fitting wasn't a problem. Opposite the vacuum test screw, there's a cast-in boss (purpose unknown), this had to be filed off before the 50 x 100 heater would fit properly. I did a lot of smoothing of the surface with wet'n'dry as well.

Testing (on the bench) was illuminating... unfortunately not in a good way. 5W really isn't much power. It took about ten minutes for a fairly paltry temperature rise. I didn't take photos of measuring this (I managed to borrow a thermal imager) but it was around 8 C increase.

There's no way that +8 C in ten minutes, on the bench, in still air, is enough for the job. However it did give me a baseline for what's needed, that being roughly 80 watts per inlet.

I also had a good scout around for heating elements and found out something that might be very useful to someone out there: multi-stranded flexible nichrome wire, insulated in fibreglass, is made and sold - just not around here. Omega Engineering (Australia) have some, but it's the devil to search for it since they don't give it an intuitive name. I'll have to keep looking and post again later. Heater tape / cord is available but it's just too fragile to survive long in this application.

There is an alternative: type K thermocouple extension wire. Radiospares sell this. Type K is a pair of wires, one made of alumel, one made of chromel. The alumel is magnetic, low resistance, and not useful as a heater element. The chromel is approximately 90% Ni, 10% Cr, and has roughly half the resistance of Nichrome V (the 80-20 Ni-Cr alloy commonly used as a heating element). It's flexible and insulated to handle the temperature (if fibreglass insulated). I'd prefer the nichrome flex cable (looking for this stuff is driving me mad, I know I saw it earlier), but the type K could be done if necessary.

[pete376403]

Flexible heating wire - I stripped some out of an old safasleep low voltage electric blanket years ago to make a heated vest. You might find one of those blankets at an opshop.
From your description the wire you are after is very similar to what I used.

Edit. I only used half of a single blankets worth of wire for the vest. I did make a a second one but never completed it. The stitching could be unpicked easy enough if you want the wire. There would be about 2 -3 meters in total.

[OddDuck]

The bike's been running with a nasty tingle coming through the footpegs and the bars, something that gets quite nasty to ride with after a while.

My first thought was that I'd overcooled the inlet stub pipes, particularly since there was unequal insulation on these (slightly thicker washers on the horizontal, it was late, I was tired, we've all been there). Cue a few weeks worth of playing with the insulation on these, with the issue appearing to get better again with each change and then coming back worse than before.

First I tried equalising the paper washers, then taking the paper washers down to 0.5 mm thickness each (worked at first), then fabricating metal top hat washers and changing out the fibre and resin insulator washers in order to run the pipes warmer (also worked at first). I found out a few things while making changes.

1) the resin and fibre insulating washers creep quite a bit under pressure and heat. Given another year or two of service, they'd have failed to clamp properly any more. They were also tight on the M8 cylinder head studs and had to be drilled out again in order to slide on and off properly.

2) it's possible to make metal top hat washers which insulate nearly as well as the fibre ones do. The trick here is to make them badly; have tapered faces, use supporting washers on the aluminium flange, that kind of thing. Poor contact between multiple layers of metal actually works pretty well as insulation.

3) M8 top hat washers can be hacked up at home without a lathe. M6 flange nuts have a 10mm hex which provides a reference surface. Bench vise, file around the perimeter to take 10mm hex down to 10mm round, a series of drills through the thread at the center and voila, ghetto components good to go.

4) the inlet pipes have quite a temperature gradient across them when running - the fuel and air mixing does suck a lot of heat in - and there definitely seems to be an optimum point of operation. Too hot and the engine's psycho loud, too cool and there's nasty combustion with rough running and loss of power. The trick is getting the right amount of heat conducted in from the engine, and that takes some trial and error. It certainly wasn't right as stock, except for running around at half throttle or more.

5) there can be quite a difference in thermal conduction between different grades / thicknesses of paper washer, particularly if they get soaked through by petrol... or not. OEM lets a lot of heat through, it appears now that this was deliberate. My aftermarket gasket paper is a much more effective insulator, but now I've run into problems with the pipes running too cold.

6) running temperature of the inlet pipes also depends on throttle position, since more fuel & air means more cooling. There's no passive solution here, if thermal conduction from the engine is right for around town, it'll be too cold for highways. If there's enough for highways, there's too much heat for town and the bike's going to get loud in traffic. This is a right pain, no wonder people go to split singles and short inlets, it's the only way to duck this particular issue short of active temperature control on the inlets.

And after all this, it's still running with a nasty vibe... I did some reading and carburettor misadjustment (or even dirt) had caught a lot of people out. Fine, it'll be into the carbies yet again. As a precaution, I pulled the spark plugs out first as a basic check of what's going on.

Horizontal cylinder: super clean, no fouling or overheating, about as close to perfect as I'd ever seen. Vertical cylinder: fouled to the point where the multimeter could measure a resistance across the plug nose, meaning it's rooted. This happened in under 500 miles, the plug was brand new just a couple of weeks ago. Maybe the carbs are delivering different mixtures, but it's doubtful that they're this different.

Further reading pointed out that a fouled plug can be the result of a weak spark. The bike's been fouling plugs on the vertical cylinder ever since I'd bought it. That's before carburettor replacement, before tuning, it's just always been like this. Right... Before going with my gut and laying down cash for new CDI's, I got the multimeter out and checked voltages with the bike on a stand and running. Maybe it wasn't the CDI's. Maybe it was the wiring. Or something.

The pickup coil resistances tested OK for ohms with the bike static (as per workshop manual), but testing while running indicated significant differences in voltages supplied to the CDI's. The horizontal is delivering between 0.8 to 1.2 Vac, the vertical just 0.2 to 0.4. It's possible that this is due to bad gapping, but I double-checked this when reassembling the engine and was happy that I'd got it right.

This seems pretty clear cut, but I went through the rest of the accessible bits of the ignition anyway. Initially the positive voltage sides of things were all running at 9V or so, which seemed to indicate a problem with the feed from battery through main relay, kill switch, and wiring harness. After a few minutes messing around and the bike running, this voltage increased to 11 V, and the coils were warm.

To my mind, this last may also be a factor present in cold starting. It's not just that the engine is cold. It's that the coils are cold too, and presumably are snorting current down to the point where supply voltage is sagging. This wouldn't help sparking, which of course is what's needed when cold starting.

Anyway... looks like it's prudent to replace the pickup coils. It would've been more prudent to do that on the engine rebuild, but hey, spilt milk and all. I'll just be grateful if this finally sorts the issue out.

[OddDuck]

Flexible heating wire - I stripped some out of an old safasleep low voltage electric blanket years ago to make a heated vest. You might find one of those blankets at an opshop.
From your description the wire you are after is very similar to what I used.

Edit. I only used half of a single blankets worth of wire for the vest. I did make a a second one but never completed it. The stitching could be unpicked easy enough if you want the wire. There would be about 2 -3 meters in total.

This is gold. Thanks mate - will do.

[OddDuck]

I called FastBikeGear to check compatibility of the CA Cycleworks coils with the Ignitech CDI's (basically they aren't; they're a good match to the OEM Ducati ignition circuitry but won't work well with the TCIP-4) and ended up having a very informative chat about ignition pickups and testing.

Apparently halving the pickup gap increases the signal by a factor of 4. It is very possible that I'm simply running too wide a gap on the vertical cylinder, given how much of an effect distance has on an inductive pickup. It was also possible that the pickup has had an insulation breakdown to the engine cases and is leaking voltage. Testing one involves draining the oil and opening the engine; testing the other is just raising the tank and getting the multimeter out again.

So tonight I was checking insulation resistances, both cold and after a few minutes idling to get the engine up to temperature. These came in fine, with no continuity measured on any scale, hot or cold. While fussing around, purely by chance, I noticed a strong jet of air coming upwards from the vertical cylinder head. It initially appeared to be coming from around the spark plug. Putting a strip of rag around the base of the spark plug didn't make a difference, then further checking by hand seemed to establish that it's coming from a place close by the rear shock mount, on the left side of the head. I couldn't trace it further. It doesn't seem to be coming from the exhaust flange, and is definitely related to the engine running.

This is worrying. The horizontal head didn't have something similar, when I quickly checked. I'll have to work out a way to trace this air jet's source properly; it also looks like it's a good idea to finally get a compression gauge with an M12 x 1.25 adaptor.

[Rhys]

Crank case breather?

[OddDuck]

Crank case breather?

Yep, almost certainly. Oops. I haven't reconnected it (need fittings to go into the tops of the pods) and the outlet for the little breather tanks under the seat is pointed right at the left side of the vertical cylinder head.

[OddDuck]

I had a few hours clear today so got into the left hand engine cover and re-set gaps on the ignition pickup coils.

The procedure is:

Fairings off
Drain oil into clean pan and set aside for re-use
Clean entire perimeter of alternator cover, especially chain sprocket area (I used kero, a paintbrush and a rag)
Disconnect everything from alternator cover
Remove kickstand bracket and gearshift arm
Undo every 6mm cap screw on cover perimeter (there's one tucked away under the clutch slave)
Using puller tool, take alternator cover off, take care to keep gasket in good shape (this can be re-used)
Connect motor turning tool and remove spark plugs
Get 0.405mm feeler gauge and 10mm spanner, tweak bracket carrying pickup coils to revised position
Explain to freeloading neighbor that rebuilding engines doesn't mean knowing how to connect bluetooth between her phone and her SUV's stereo
Replace cover after wiping gasket surfaces with a clean rag
Reassemble and reconnect everything
Go to turn motor over, realise that oil isn't refilled, fuck fuck fuck that was close, refill oil
OK, try motor now, test pickup coil voltage.

At this point it got a bit Princess Bride, there was some disappointment and I had to get used to it. Coil voltages hadn't increased dramatically, they were still around 0.2 Vac, however the bike was running in a much more stable fashion.

Something that I'd noticed yesterday was that at idle, starting from cold, the bike was only firing on one cylinder. The second would kick in if the revs were increased very slightly. It's odd how an effect like this is only obvious once I was actually listening for it. This was gone, post 4 hour tweak. The bike caught on both cylinders and ran better. The subsequent test ride confirmed this.

Bar tingle is gone. There's still some vibration, I believe it's linked to the inlets running too cold, but it looks like the adjustment worked to sort out the major problem.

That said, it looks like time to replace a few major ignition components. The pickups and CDI's are 22 years old and look every day of it. This adjustment will keep me going for a while, but it'll be best to get ready for replacements soon. Note that in the photos, I've got the feeler gauge transverse (it made a more clear image), but in the actual adjustment the blade was parallel with the flywheel axis.

[OddDuck]

Quite pleased to see the bike make it to this mileage. I know it's nothing compared to what most Japanese sportsbikes can do but I've got to wonder how many of the carbie SS got this far. Just missed out on the 60...

329329

[OddDuck]

South Island trip!

Multiple delays... bad weather, major earthquake, worse weather, and then the third of us couldn't make it. The damn thing was jinxed. Fuck it. Go anyway.

At least, that was the plan. I'd taken the bike out for a proving run the day before sailing and came back with a rear tyre full of Tyreweld (pando?) due to glass... it was repairable but I'd had to run some distance on 20 psi or less and lost most of the rubber, the tyre going from nearly new to just this side of WOF-illegal inside an hour.

It was repairable. A plug would have been $45 or so. I know the sidewalls would have been worked pretty hard, the tyre was going to come back from the trip worn out, why muck around. I've taken a plunge and changed for a Bridgestone T30 touring tyre. A shout out is due to the mechanics at TSS Lower Hutt, who stepped up from a hectic workload and sorted it in time for the ferry - thanks guys!!

And away we went... I'll avoid a hyperdetailed route description. We had a lot of fun, highlights were the Buller Gorge, the run around Lake Brunner, the West Coast run through Punakaiki, the history at the Blackball pub, and the run north from St Arnaud past Tophouse deserves special mention. That Tophouse road (and carrying on through Golden Downs) is just amazing. Maps may show it as gravelled, it's fully sealed now.

The Picton-Blenheim-St Arnaud-Murchison road is now the main route and is chocka with trucks, caravans, campervans, everything really. St Arnaud through to Murchison is almost completely solid yellow lines, both sides of the road - no legal passing except in a couple of spots. There are quite a few roadworks, one of which is dangerous because they haven't bothered cancelling the old road markings. If you get a bit zoned out and follow these without thinking (it's an old one lane bridge, now doubled), the markings feed you onto the wrong side of the road, or into the bridge endposts. I think that one's just a bit south of St Arnaud.
There is quite a bit of recent chip seal laid down, if you see a 50 km/h sign, expect loose gravel on the road from recent patches.

Driver behaviour was pretty good - a lot of courtesy shown, very little or no aggro.

Ferries: Interislander was good, Bluebridge was good too. No problems with either service.

Bike went well, new tyre handles a bit different to the old S21 and took a spot of getting used to, but I think I'm warming to it now. Overall a fantastic trip and I'm really happy we did it.

[SVboy]

Nice! Good to se you get some rewards for your efforts!

[OddDuck]

A while ago I had a spot of spare time, enough to run through some calculations of what's needed for the inlet manifold heaters. There are quite a few constraints:

43 mm inlet manifold diameter
50 mm available straight length
80 watts needed per inlet (more about that later)
12 V supply
Warm-up time of roughly 10 to 20 seconds before trying to start the engine
Heaters will have to run until heat from cylinder head takes over

It turned out that if I lathed up a 55mm OD, 43mm ID tube and ran a drill lengthwise through the perimeter at regular intervals, allowing a 3mm pitch spacing, I'd get roughly 50 passes. Going end-to-end is preferable to spiral wrapping because it allows the heater mount to be split lengthways, which is really the only way it can be fitted anyway. It can then be secured with hose clips or springs.

Skipping over a lot of calculations, it works out that a single row heater would need insulated wire of between 1 to 3 ohms per meter in order to deliver the necessary power. Power drawn from the wiring loom is a consideration, too. 160 watts at 12 volts means drawing 13 amps. I have a spare 12V line off the horn which is switched through the ignition key, but 13A really needs a dedicated relay with its own fuse. I'd like to include some device for reducing power drawn in steps so that warming can be reduced as the engine warms up, before finally being switched off completely.

Anyway... I'd bought a couple of cheap electric blankets off Trademe and spent tonight taking one apart. I think I've learned a hard lesson here about reading things properly: it's not a low-voltage blanket, and the 13 meters of heater wire I've pulled out of it has a resistance of 61 ohms per meter, with both inner and outer conductors twinned up. Won't work. Damn. At this point I think I'll skip doing the rounds of the op shops and just see what I can order via Amazon / Youshop etc... just so long as it's on its way.

[Ocean1]

On the hydro schemes the big cats point blank refused to start most winter mornings.

Until you kicked some diesel soaked rags under the sump and lit 'em.

Only takes about 10min...

[OddDuck]

Some things I'd found out over the last few weeks worth of reading, thinking, playing with ideas, and running calculations. No particular order, although they're numbered.

1) serious amounts of thermal wattage are needed to cope with latent heat of vaporisation at high throttle settings. Obviously cooler inlet air means better volumetric efficiency, but below a certain point fuel will simply drop out of suspension and the engine will be drawing lean air-fuel mixture and liquid fuel. Generally this thermal wattage simply comes from the ambient air and isn't a problem, but it can be an issue in very low ambient temperatures.

2) it's possible to warm inlet air, inlet manifold walls, or carburettor bowls, or all three. All of these have been done before, this isn't new.

3) petrol will start condensing out at surprisingly high temperatures, once fuel-air mix comes in contact with an object. Things really don't have to be that cold for it to happen. I found a paper (OK, from 1921) which listed detailed work carried out on two long-gone blends. Of key interest was the temperature at which condensation fell to zero, it was around 60 to 70 degrees Centigrade. No wonder inlet manifolds are run hot. Obviously 95 octane isn't whatever was available in 1921, but the basic effect won't have changed.

4) petrol boils at surprisingly low temperatures, just a few degrees up from the earliest condensation temperature. This would be why carburettors are always insulated from their engines, I guess... boiling a carb bowl dry would be something of a problem.

5) it's amazing what can be bought for a smartphone these days, you can get thermal cameras from FLIR and borescopes from various companies as well. Both could be very useful tools for garage work.

6) using electric heat is pretty much the only way to warm up the inlet manifolds (and possibly the carburettor bowls) before attempting an engine start; power demands are far too high to keep doing this for long once running.

7) some carburettors will stumble on acceleration due to fuel condensing out and creating a temporary lean condition. This isn't to do with fuel being squirted directly onto manifold walls, it's something to do with changes in air pressure inside the manifold and therefore a change in the fuel-air mix dew point. Inlet manifolds - or their hotspots - have to be hot enough and have enough thermal mass to cope with transients because of this.

8) heating needed to the inlet manifolds is almost certainly not proportional to throttle setting. There'll be effects with fluid boundary layers and so on; there'll be a relationship between the two but it won't be linear.

9) using cylinder head heat (through bulk conduction) or exhaust header heat (through ducted air) is the tried and proven way of providing the thermal energy needed to deal with the heat of vaporisation issue. At the same time, it's got to be controlled somehow.

This last point is where the headaches begin...

Low ambient temperature: more heat.
High throttle setting: more heat.
Cold fuel, as encountered first thing on a winter morning: more heat.
And vice versa, of course, the heat requirement is anything but steady.

I want those manifolds to run at a fixed temperature, effectively, with enough thermal mass to cope with transient loads. That isn't too hard. I could just do what Ducati did in the first place and run the inlets so that they're stinking hot no matter what happens, but that means a return to ear-splitting noise in 50 zones or downtown, and I'm not keen on that idea.

So, some options:

1) controlled thermal conduction from the cylinder heads.
2) drawing air around the exhaust headers and blowing it onto the inlet manifolds, controlled via proportional diverter flaps or speed-controlled fans.
3) inserting a line from and to the oil cooler and using engine oil to pre-heat the inlet manifolds, control via thermostat.
4) high thermal conduction off the cylinder heads - enough for sustained half throttle operation or so - and variable speed fan cooling of the inlet manifolds if they get too hot.

4 is about the only option that I can see being practical enough to work. I'd go to aluminium top hat washers to increase thermal conduction, and then it's just a fan blowing onto a heatsink clamped around the inlet manifold, the heatsink possibly with the cold-starting heater built into it.

I'll have to work out a cheap and reliable means of control, possibly bimetallic switches and in-line resistors rather than something complex. The fans are available, the heatsink and whatever ducting was needed would have to be made, but it's within reach for a home machinist.

[OddDuck]

On the hydro schemes the big cats point blank refused to start most winter mornings.

Until you kicked some diesel soaked rags under the sump and lit 'em.

Only takes about 10min...

Now there's a picture for starting a motorbike on a cold morning in suburbia!!

[pete376403]

A while ago I had a spot of spare time, enough to run through some calculations of what's needed for the inlet manifold heaters.
Anyway... I'd bought a couple of cheap electric blankets off Trademe and spent tonight taking one apart. I think I've learned a hard lesson here about reading things properly: it's not a low-voltage blanket, and the 13 meters of heater wire I've pulled out of it has a resistance of 61 ohms per meter, with both inner and outer conductors twinned up. Won't work. Damn. At this point I think I'll skip doing the rounds of the op shops and just see what I can order via Amazon / Youshop etc... just so long as it's on its way.
The devil is in the details...
If you want I can give you some of the LOW voltage single core wire. I have two 3 metre lengths plus what I used to make up one of the heated vests (about 5 metres maybe. I'll check the resistance tomorrow -good meter is at work.

[AllanB]

Inlet heaters.

Here's a couple of options to consider. They may be able to be modified to suit. For the price the first ones would be worth playing with just to see if it helps the issue.



http://www.ebay.com/itm/HOT-Universal-Grip-ATV-Motorcycle-Heated-Grips-Inserts-Handlebar-Hand-Warmers-/141677815322


http://www.webbikeworld.com/r3/heated-motorcycle-grips/

[Voltaire]

Inlet heaters.

Here's a couple of options to consider. They may be able to be modified to suit. For the price the first ones would be worth playing with just to see if it helps the issue.



http://www.ebay.com/itm/HOT-Universal-Grip-ATV-Motorcycle-Heated-Grips-Inserts-Handlebar-Hand-Warmers-/141677815322


http://www.webbikeworld.com/r3/heated-motorcycle-grips/

We used to call it " Heat Trace Cable" when I worked in the UK on hot water boiler systems.

http://www.ebay.com/itm/Minco-12V-Self-Regulating-Heat-Trace-Cable-for-Freeze-Protection-/262588585913?var=&hash=item3d237fd7b9:m:m0RdSP09HC0yElKHvPPPGYQ

I've given up on the non choke FCR's on my 900SL and refitting a set of stockers when I get an airbox....have had to put up with riding a Guzzi Lemans 2 and Vespa PX 200 over summer :mellow:

[OddDuck]

We used to call it " Heat Trace Cable" when I worked in the UK on hot water boiler systems.

http://www.ebay.com/itm/Minco-12V-Self-Regulating-Heat-Trace-Cable-for-Freeze-Protection-/262588585913?var=&hash=item3d237fd7b9:m:m0RdSP09HC0yElKHvPPPGYQ

I've given up on the non choke FCR's on my 900SL and refitting a set of stockers when I get an airbox....have had to put up with riding a Guzzi Lemans 2 and Vespa PX 200 over summer :mellow:

Might be able to help you there, I have my old airbox sitting under the house... the lid's been opened up and some of the side reinforcing has been trimmed, but otherwise it's still good. PM me if you want it.

[OddDuck]

Inlet heaters.

Here's a couple of options to consider. They may be able to be modified to suit. For the price the first ones would be worth playing with just to see if it helps the issue.



http://www.ebay.com/itm/HOT-Universal-Grip-ATV-Motorcycle-Heated-Grips-Inserts-Handlebar-Hand-Warmers-/141677815322


http://www.webbikeworld.com/r3/heated-motorcycle-grips/

Thanks, have heard similar already and had a look, then and now... unfortunately this project is riddled with fiddly problems. Should work, could work, but just doesn't quite work.

The usual handlebar grip heaters are too long. I've only got 50 mm of clear straight pipe to wrap, and the heaters don't cut down.

Also, handlebars usually never get to hot enough to melt velcro... the inlet manifolds, if running at the correct temperature, are right at the limit for most plastics. Nylon, if that's what velcro is made from, is going to struggle. Sooner or later I'm going to ride on a hot enough day that anything marginal will just melt. Unfortunately that rules the Oxford overgrips out, it's a shame because they actually would go straight on.

The other thing is the power needed. I just don't think the grips will do more than help; they won't nail the problem. The manifolds cool down amazingly fast during startup, as judged by touch. When I ran the calculations for the wattage needed to match the heat of vaporisation during startup, what I found was that even at 450 RPM (starting cranking speed), about 40 watts is needed. Throw in cold fuel + cold air + idling at 900 RPM and 80 watts per manifold does start looking reasonable.

I've had another good long look tonight and I reckon I've got a solution to try:

1) combined split heater and finned heatsink, to be machined up out of aluminium bar or plate

2) monitor thermometers to be installed in the instrument cluster so I can see what's happening as I ride

3) blower fans installed in front of the carburettors, in the empty space where the airbox used to be

4) piping between fans and finned heatsink, with ducting around the heatsink

5) automatic control for heaters and fans so I don't have to worry about switching stuff on or off while I ride.

6) possibly ducting between finned heatsink, wrapping around cylinder head, to exhaust header. My preferred solution is still to warm the stubs up off waste engine heat, rather than cool them

I'll be shopping for a few of the things needed and hopefully placing orders soon... thinking and reading only goes so far, sooner or later it's time to muck in and accept that it won't be perfect or even work first time.

[OddDuck]

Well, now... found this:

http://www.shell.com.au/motorists/shell-fuels/msds-tds/_jcr_content/par/textimage_278c.stream/1468566928711/e836453c7e8096af53542f5d917c37c3850b70bf318f3a4fe3 ac863a74b2ec3f/pulp-tds-commercial.pdf

Technical data sheet for 95 Unleaded. There isn't anything about condensation but the boiling points are instructive.

I've also placed the first orders on Amazon and been finding it very useful as a learning tool. There's a lot available these days that I wouldn't have expected... random browsing is opening up a lot of possibilities. I'm not sure I'll actually use this, but it's certainly intriguing:

https://www.amazon.com/gp/product/B00K75QRZA/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=AFHAE9RJVUMB

Digitally settable thermostat. It's not a sophisticated controller, this is simple slam-bang on-off control. It will oscillate around the setpoint when in use, but if the oscillations can be kept within a narrow enough range, it could work. Certainly being able to combine digital temperature readout with control in one unit is very useful.

[pete376403]

I measured the resistance of that cable - 2.2ohms for 3 metres. Any use?

[OddDuck]

I measured the resistance of that cable - 2.2ohms for 3 metres. Any use?

That's perfect, yes please. PM on its way.

[OddDuck]

It occurred to me that before making any changes I'd better be a bit more sure of what was actually happening. I think the problems are down to thermal effects; so far all I've been doing is pulling over, yanking a glove off and dabbing a fingertip to guess at temperatures. It's not really measurement, just informed guesswork. I borrowed a thermal imager, went for a ride, and shot some images.

The first three photos are to show the angles I used and the targets of interest. These are:

1) the vertical cylinder head and its inlet manifold

2) the ignition coils

3) the carburettor bowls

I've gone on for long enough about the inlet manifolds but the other two deserve a bit of an explanation. I'd found out by accident that the ignition coils get surprisingly warm during operation. I already know that there's a knock-on effect to voltage supply to the coils; as they warm up the supply voltage rises to the nominal 12 V, presumably from resistance increase inside the coil itself. It then follows that if the coil gets hot, resistance increases further, this affects current flow to the coil and its ability to store energy for the next spark, and so a hot coil would adversely affect ignition.

The coils are tucked under the fuel tank, pretty much directly over the front of the vertical cylinder head. They're perfectly positioned to get cooked by rising heat, if slipstream isn't present. Maybe this is one reason the bike starts to behave badly in traffic. At least, that had been my thinking. I hadn't measured it yet.

The carburettor bowls had seemed to get cooler, when quickly checked by hand earlier. If they're getting too cold then presumably this would affect fuel vaporisation. I hadn't measured this either.

So, three simple shots to take. Go for ride, pull over, quickly get the imager out of the tank bag and shoot by the side of the road. Simple enough. The first three photos (the normal ones) show the angles I used. The inlet manifold was easy enough, that's just the flank of the bike. The coils required lifting the fuel tank and were imaged from the side and over the windshield, from the front. The carburettor bowls had to be imaged from under the left clip-on, through a lot of clutter.

The first three infrared shots were taken with the ignition switched on but the engine not running, showing the coils warming up under supply voltage. This was over roughly three or four minutes.

[OddDuck]

And now starting... I cranked the motor from cold, got it to the point where it would just maintain idle, and took a few images.

329629

There were more, but this one shows the basic idea: the inlet manifold takes much longer to warm up than the cylinder head. Head temperatures got to 45 C or higher very quickly after the engine caught. Manifold temperature appeared to lag behind for some time.

The manifold is shiny metal, rather than painted or oxidised... that's a problem for a thermal imager, because shiny won't let heat out or heat in. It acts like a mirror instead and reflects the surroundings. The images can't be taken at first glance. There's an oxidised flathead screw covering the vaccum tap, though, and that's a good target (just to the left of the crosshairs in this image). Image colour can be used to assess temperature, you don't have to rely exclusively on the crosshairs reading.

[OddDuck]

Right, five minutes down the road, bike idling roadside.

[OddDuck]

Another ten minutes down the road, rolling at a steady 50 k's the whole way. I took the time to get the seat off and put the tank up, taking two images of the coils. The carburettor body is the near black object, with clutter everywhere.

[OddDuck]

At this point I'll cut the images down to stuff that might be interesting in terms of things like warm tyres, muffler temps etc. I went up a hill, rolled around in suburbia for a while, came back on the motorway, then rolled slow (1st gear, to mimic traffic) home, trying to get the engine to behave badly before putting the tank up again to have a last look at the coils.

Some early conclusions:

1) coil temperature doesn't seem to be affected much by slipstream, it gets to high 30's and seems to stay there. Further checking is needed, though. I haven't tried this during a hot day downtown, when the bike thundering tends to become a real problem, even with the inlet manifold insulators.

2) inlet manifold temperature moves quite a bit, depending on ambient, throttle loading, slipstream etc. The manifolds seem to be running at roughly half the cylinder head temperature, with OEM gaskets and the fibre insulating top hat washers I'd made up.

3) bar tingle definitely comes back below a certain inlet manifold temperature, I think around 65 C, and goes away above about 70 to 75 C.

4) there is a cooling effect on the carburettors from the fuel. So far it only seems to be a few degrees, but I haven't had any chance to go beyond 1/8th throttle for any length of time. I don't know how or if this crosses over to bar tingle or excess noise, though.

5) no matter how quickly I pull over and get the imager out, I'll never get accurate pictures of what's happening while I ride. The manifolds change temperature too quickly, as seen by monitoring for a while after getting off while leaving the engine idling. On-bike logging is needed to get decent data.

It was still a decent start and worth doing again during hotter conditions. Ambient for tonight's run was around 17 to 18 degrees.

[OddDuck]

Finally got around to the 3000 mile valve check / service... post rebuild, clearances should be checked at 1000 miles, then back to the regular 3,000 mile intervals. I wanted to pull every shim and measure length so I'd know what to order, if clearances changed.

This meant finding a way to lock the valve once the opener shim was removed. This has to be done, otherwise there's a chance that the valve will drop into the cylinder. The valve stem seal will probably catch the valve by the collet groove, but if that valve goes in then it's frame off engine and head off cylinder time.

Holding the valve in place against the piston crown is possible, but that gets fiddly... there's only one place in the cam rotation where the top rocker will slide across, allowing access to the shim stack, and that only seems to happen with the piston well down in the cylinder. I'd have to remove the timing belts to do it. Easier to secure the valve.

I tried a twist of wire, with insulation left on for grip, but this didn't work particularly well. Oil-soaked PVC insulation on chromed, polished, oiled valve stem just doesn't grip particularly well, especially since the wire has a habit of opening up again. I also tried a loop-and-choker arrangement of wire and cable tie, but the cable tie didn't slide up the wire properly, cutting into the soft insulation instead. Frustrating.

In the end I just used 3mm wide cable ties directly on the valve stems, between valve guide seal and opening rocker arm fork. This gripped securely. No issues using it - there's enough clearance to push the opening arm down far enough to get collets and shim out - but I had some trouble removing it. I really didn't want to mark the valve stem or cut into the valve guide seal.

In the end using sidecutters straight through the ratchet mechanism of the all-plastic tie, avoiding either side of the loop and never getting the cutter jaws close to the stem or guide seal, worked. The little tongue of plastic that serves as the ratchet ended up popping out, just waiting to jam in somewhere, so that had to be found and removed.

Disposable foam earplugs were used to prevent collets / bits of cable tie falling down the oil drain ports into the engine. One note about these, there is just one on the horizontal head, but there are two - one each side - on the vertical head. It pays to get both valve covers off and plug both holes before starting work.

I'd seen a kit from the USA for this kind of work which featured rubber-jawed locking pliers. There are also specialist tools around for holding down the opening arm and locking it down. Initially I'd thought these were pricey luxuries; after the ordeal that was yesterday's effort of pushing with an oil-soaked screwdriver while trying to refit collets, I'm beginnning to see the point of having these. It got awkward. I was down by the front wheel and also working under the tank, access was poor.

I need quite a few shims anyway - there's been some movement, and one valve has moved 0.004" on both opener and closer - so it's shopping time. The MBP valve collets are holding up well but there's a little bit of settling in wear or deformation showing.

[Ocean1]

May not work, there, if you can't live with the piston at bdc, but several time's where the alternative is removing the head I've simply fed compressed air into the cylinder via a modified plug.

It's not mechanically 100% secure, but the valve gets maybe 100kg closing force. On a conventional setup it's enough to pop collets out with a hammer and socket. On a conventional setup you also need a spring compressor that clamps under a rocker shaft or head stud nut.

[OddDuck]

May not work, there, if you can't live with the piston at bdc, but several time's where the alternative is removing the head I've simply fed compressed air into the cylinder via a modified plug.

It's not mechanically 100% secure, but the valve gets maybe 100kg closing force. On a conventional setup it's enough to pop collets out with a hammer and socket. On a conventional setup you also need a spring compressor that clamps under a rocker shaft or head stud nut.

I thought the experienced hands would have a trick or two... yep that'd work brilliantly. I'd have to (finally) get an air compressor and source the adaptor but there'd be no farting around with bits and bobs inside the rockerbox. I'd have to remove the relevant timing belt though, the pressure would drive the piston to BDC and there might be issues with rockers and camshafts.

One of the joys of the desmo system is that there aren't valve springs, very low levels of mechanical force are needed to strip the top end of the valve gear. There's a closing spring for the closing arm but that's all, a half-decent lever is all that's needed to work that.

[Voltaire]

Spent a few hours on Saturday putting the rebuilt stock carbs back on only to find when I went to start it up fuel pissed out the carb...
Took it all apart again an found the float on one carb sticking open due to crap in inlet.
Cleaned it all and put it back together, set the carbs at 1.5 turns out and started it up....ran like shit, flames spitting out of both ends.urry

Gave up and had a selection of craft beers and a curry. Was at the point of taking it to someone else.

The air/battery box is such a PITA to fit I left it off and you can run the engine with the electrics just sat in the space for test purposes.
The spitting was caused by lean idle, google agreed that 3.5 was the correct setting, which it turned out was correct as started up and ran with no choke from cold.
I was a bit surprised by that. Carbs have had a Dyna summit rebuild kit fitted.

Encouraged by this changed the oil, fitted new plugs and cleaned engine.
Did a final assembly and took it for a 35KM spin out to the Airport and back.

Starts easily, idles at a 1000 RPM, pulls cleanly up to the 7500 I tested up the Hillsborough incline section of motorway, will run to below 3000 without the usual Ducati juddering.
Cut out twice after the deceleration but that may be fine tuning as its got Termis on it.

Conclusion: Kehin Flatslides on a road bike are a nice bit of bling but , the increase in power if in fact there is any ( can' say I noticed a lack of it) is not worth the grief of having an engine that is hard to start.

I did notice that the engine was running hotter than I would expect but thats a job for another day, Ducati 900SL can now be easily started and taken for a ride :yes:
Mines got a Yoshimura volt meter/cloc/Temp guage, I'll see where the sensor is as it was reading 61 degrees when I got home.

[pete376403]

Supercheap have a range of compressors that would be suitable. Nothing fancy but they do the job. $125 and they have a good range of accessories. No sparkplug adapters though.

[OddDuck]

Voltaire - good to hear, but... sorry I'm going to be a fussy bastard here...

Check your plugs, I suspect that it'll run super rich once warmed up if it's starting without choke. Surprising amounts of heat coming off the engine is something I've been through already and it was associated with running over-rich.

Airbox and filter medium (or lack thereof) will affect starting and idle quite markedly, if you got it tuned for starting with these removed then it's going to be a bit different with them fitted. At least the pilot fuel jet screw is accessible easily, it shouldn't be hard to tweak it again if necessary.

If the plugs are fine then ignore the above, just ride the thing.

[OddDuck]

Keihin flatslides: I reckon they're awesome but the as-arrived tuning is probably dicey. That said, they've worked out very well for me... power improvement would have to be dyno'd (together with decent tuning) but for me at least there was one hell of an improvement in rideability, straight out of the box.

[Voltaire]

Voltaire - good to hear, but... sorry I'm going to be a fussy bastard here...

Check your plugs, I suspect that it'll run super rich once warmed up if it's starting without choke. Surprising amounts of heat coming off the engine is something I've been through already and it was associated with running over-rich.

Airbox and filter medium (or lack thereof) will affect starting and idle quite markedly, if you got it tuned for starting with these removed then it's going to be a bit different with them fitted. At least the pilot fuel jet screw is accessible easily, it shouldn't be hard to tweak it again if necessary.

If the plugs are fine then ignore the above, just ride the thing.

Good points, will back off idle mix next, check the plugs and see how that goes.
Be nice to have it sorted as being a hard starter means its at the back of the queue for rides.

Monday: Ambient Temp 20 degrees according to on bike guage, would 'catch' with no choke but die, part choke started and idled, choke off after a min and idle.
No unburnt fuel smells from zorst. Best cold start ever for that bike

I spent a lot of time sorting out my Guzzi carbs and its pretty good but does not like running low road speeds to too long ( aka Vintage Bike run)

[Voltaire]

Keihin flatslides: I reckon they're awesome but the as-arrived tuning is probably dicey. That said, they've worked out very well for me... power improvement would have to be dyno'd (together with decent tuning) but for me at least there was one hell of an improvement in rideability, straight out of the box.

I found the rideablity excellent with mine, just did not like starting.

I probably have too many bikes that need attention so the ones that go and don't cause bother get used....BMW's mainly:wacko:

Dyno tuning is the way to go :2thumbsup

[OddDuck]

Thanks to donations of low voltage heater wire (thanks Pete) and finally getting some spare time and energy, I had the first go at the inlet manifold heaters and a cold start test tonight.

Basic specs: heater coils are 1 ohm each (cold), that works out to roughly 74 watts if they're run in series off 12V. Power supply was a mostly-rooted battery that I hadn't got around to disposing of yet. The setup's basic. It's fast, cheap and nasty. That's deliberate, there's no way I'd go on the road with something this rough... this is a simple practical test and nothing more.

Right, before people get their hopes up: it failed. It didn't warm the inlet manifolds up more than about five degrees and there was no success at cold starting, when I gave the starter motor a few cranks to see what'd happen. I did learn a couple of things, though.

1) that old battery really is stuffed, I'll have to sort out a mains 12V / 6 A power supply with a short circuit protection for any real testing. Power will have to be applied for at least five minutes continuous. This sort of time will have to be drastically reduced for any real world system.

2) thermal coupling between the heater and inlet manifold is very poor. A layer of insulation over the top would help, that's an option for later, but I think that what's really needed is for the heater wire to be completely buried inside aluminium. For that I'll have to machine something up.

[OddDuck]

Tonight's effort was to try to insulate the manifold heating elements, and (second) to try heating the carburettor bowls.

A spot of muffler wrap cut to size, a hose clamp to hold it on, and I connected a borrowed 10A-capable power supply to the heaters and had at it. Findings:

1) the manifolds get quite warm at the carburettor end, less so at the cylinder head
2) even with the insulation on, this setup still takes a good five-ish minutes to heat up
3) peak temperature was approx 40 C at the vacuum gauge screw head, this was with roughly 36 watts of heating
4) it helps starting but there's no way it's an instant roar-to-life solution.

It does help. Ambient was 13 C. At this sort of temperature, previously I'd have had all sorts of fun and games trying to get the engine to catch while cold-starting. I was deliberately not using the accelerator pumps to squirt petrol down the inlet manifolds before cranking the motor, it took a bit of cranking but the motor did start to catch, much sooner than usual.

I then tried using a very cute pair of 40 W cartridge heaters (for 3D plastic printers) on the carburettor bowls. There a quite a few of these floating around these days, they're useful little beasts. Purely by chance, these fit into the idle mixture adjustment screw's bore quite nicely.

Initial tries were very promising - it didn't take long to warm the carburettor bowls up to approximately 25 C, and starting did seem to improve - but I can't take the results as definitive. The cylinder heads had warmed up quite a bit from previous cranking / starting / idling, and this would have helped starting too. The real test is with the motor overnight-cold.

[OddDuck]

Reckon I might have a result.

Tonight I tried starting from cold (14 C) with the twin 40 watt cartridge heaters in the carburettor bowls only - no power applied to the inlet manifolds.

I ran these heaters up until I got 30-ish degrees on the carbie bowls and then tried the starter.

Instant start and run, no issues with idle, the motor caught straightaway. No tricks with using accelerator pumps to prime. This was exactly the result I wanted.

I've now removed the experimental gear and put the fairings back on, I'm happy enough with this result that I won't try running inlet manifold heaters and carb bowl heaters together again. There's really only enough oomph for 80 watts anyway.

So, now to figure out a way to couple 40 watts into the carbie bowl and thus the fuel... It looks like the way to go is to make some kind of replacement for the 14mm hex drain bowl screws, something carrying both the heater element and a temperature sensor. That'll involve detailed measurements of the Keihin original part and then designing and machining something, but once made, it's a screw-in, bolt-on modification.

[OddDuck]

About a week ago I'd bought some sensors and thermostats off Amazon. I got around to testing them today.

First up was this wee beastie: www.amazon.com/gp/product/B00C2NQ83Q

About a year or so ago I'd been on a ride in the Wairarapa when the battery charge warning light came on. I pulled over, left the motor running, checked the headlight and sure enough it was dim. I'd been through this once before, much closer to home. The charging system wasn't working. The charge warning light only comes on once voltage is down below 11 V, in short, once most of the battery charge is already gone.

Uh oh. Abandon ride, switch headlight off, just try to get home. I nearly made it and had to get a jumpstart at Caltex Rimutaka (always look for a bloke with a ute, they've always got jumper leads). In the end I made it back without the need for a tow, but Ducati's warning light system really did leave something to be desired... I needed to know immediately when the rec-reg or the alternator (or both) failed.

Hence the little voltmeter. There are a few of these floating around, very simple devices with two leads that serve for both power and sensing. If I'd had this on the dash then I'd have been able to see in real time what was happening with battery charging.

I did want to test it first though, hence the setup on the bench with power supply / test voltage unit and high-end DVM borrowed from work. The little meter aced it. I won't go through the table of numbers, it's enough to say that the meter is within 0.05 V anywhere between 6 to 15 V. It's well within the accuracy I need for this kind of work. Supply is around 20 mA so it won't load the loom up significantly.

The next goodie was this: www.amazon.com/gp/product/B00D7AEKMO

I'd bought two, intending to check various temperatures through the inlet system and on the engine while riding. I only powered one up and immediately decided that I didn't want these on the bike. The reading dropped to 0.00 occasionally, the display was twice as big as the voltmeter, and the blue LED was way too bright. Various reviews had said the same. Red LEDs next time. Oops.

There were also thermostats, these being very simple on-off temperature controllers that switch a relay: www.amazon.com/gp/product/B00K75QRZA

I got 3 of them. I tested the thermometers as via the photos, in a pot of water on the stove against a couple of trusted thermometers, one a professionally calibrated unit borrowed from work. The probes are widely separated in the pot, hence the use of an eggbeater to drive turbulent stirring of the water.

They're quite good. Basically, between the different thermal lags of the probes and the unknown uniformity of the water temperature, I couldn't pick any significant difference in reading. It was far from a complete, pure, scientific test, I should have started at 5 degrees with ice water and worked my way up from there, stabilising the temperature at various intervals and running the reference thermometer around the pot to check uniformity as well... but stuff it, this'll do. Within a degree would be good enough and I think these are within 0.5 C or better.

The thermostat has a delay (hysteresis) built into its switching - it'll go past setpoint, either up or down, before it flips the relay. I guess this is to avoid buzzing if it's got a fast load of some kind. Anyway, the relay's there to connect a fan or a heater to power, it's got a digital setpoint adjustable via pushbuttons, all I have to do is put the thing into a weathertight box of some kind and I'm away.

[BMWST?]

why not a mains supply set up to warm things up when at home.probably the most common scenario anyway.Cold Kiwis and the like might require a second battery?

[OddDuck]

why not a mains supply set up to warm things up when at home.probably the most common scenario anyway.Cold Kiwis and the like might require a second battery?

Sometimes I've taken the bike to work and the day's got cold, sometimes I'm on the road on a multi-dayer and it's first thing in the morning in an unfamiliar town. If it's on the bike as part of the bike then it's with me.

When finally built and installed, it'll be something small, cheap and light. It'll be simple. The amount of work I've put in will look ridiculous but this is one of those jobs where most of it is finding out how to do it.

[BMWST?]

Sometimes I've taken the bike to work and the day's got cold, sometimes I'm on the road on a multi-dayer and it's first thing in the morning in an unfamiliar town. If it's on the bike as part of the bike then it's with me.

When finally built and installed, it'll be something small, cheap and light. It'll be simple. The amount of work I've put in will look ridiculous but this is one of those jobs where most of it is finding out how to do it.
sure is it is an interesting read

[pete376403]

What size battery does the bike have? 12volts and 40 watts should be around 3.3amps. A good battery should be able to handle two of these for a few minutes or more, seeing as now it's not going to cranking the starter motor for extended periods. Maybe you could look at a lithium battery, as the initial discharge running the heaters would bring up the voltage for the stating/running duties (if I understand how those things operate.)

On another topic - do you have any skill in programming? Does this mean anything to you? "The program is written in C.

The sensor output is applied to a 10 bit A/D convertor. The A/D results are processed via an exponential running average filter. 300 samples are taken at 20ms intervals. Next a mean average is taken of the middle 10% of the samples. This result is then displayed." and

"I used a 18F2685 for the gas gauge. It's mostly overkill, but I had some on hand from another project. Plus, it's better to have too much room for program and memory than not enough!"

[OddDuck]

Hi Pete,

The bike battery is a brick, a 12V 14 Ahr Katana (a Yuasa made with recycled materials). It's heavy, but I've had one before which survived horrible abuse (repeated run-flats during winter etc) so I've decided to stay with them. It's got plenty of capacity for running 80 watts for about thirty seconds, which is the target for the cold-start system.

With your question about C programming: no, I made a life decision two decades ago to stay the hell out of programming, I have not regretted this choice. That said I can answer some of it:

The sensor output is applied to a 10 bit A/D convertor. The A/D results are processed via an exponential running average filter. 300 samples are taken at 20ms intervals. Next a mean average is taken of the middle 10% of the samples. This result is then displayed.

It's a basic technique for screening out electrical noise.

The sensor (whatever it is) is analogue; it'll be putting out a voltage or a current in response to environment. The trouble is that the output has to come out from inside a casing and then be transmitted over leads. Casings and leads can be affected by magnetic fields, radio, thermoelectric effects in the leads, capacitive coupling from nearby electronics, that sort of thing... there'll be noise spikes up and down all over the signal. The spikes may actually be bigger than the signal, but they'll usually be centered on it.

A / D converter: a device that takes an analogue (linear) signal and converts it to a set of digital levels, i.e. a number. Once this is done, the signal is no longer anywhere near as vulnerable to outside noise because there's a very high difference between a 1 and 0; in digital systems these are expressed as voltage levels. O is usually 0 to 0.2 V, 1 is usually 4.2 to 5.2 V. It takes one hell of a noise spike to interfere with that, which is the big advantage of digital.

Exponential average running filter: Probably a microprocessor doing some magic. The bit that's important is that it takes 300 samples, which still have the noise from the sensor all over them. The A / D can only work with what comes into its front end.
The filter grabs the lot, looks at the spread of the results, then grabs the 10% in the middle, averages those, then displays that number. The digital output would be unreadable without this filter, the display would simply be trying to show a different number every 20 ms. As it is, if I read this right, the display should update every 300 x 0.02 s = 6 seconds, so it'll look a bit slow in responding to change.

This kind of filtering is always a tradeoff between minimising noise and retaining a fast enough response, so it's usually tuned for the type of sensor and the usual operating environment.

I used a 18F2685 for the gas gauge. It's mostly overkill, but I had some on hand from another project. Plus, it's better to have too much room for program and memory than not enough!

Google 18F2685 - I think it's probably some kind of integrated circuit, likely a microprocessor and memory chip. It's probably not a gas gauge, it's a device used to read one.

[pete376403]

Thanks for the input. The item in question is a fuel gauge that was designed and build by a guy on advrider.com. It used a pressure transducer(?) measuring the weight of fuel in line from the tank, and from there calculating and displaying the amount of fuel left in the tank. From there it morphed into a multi function display for temperature, road speed, gear position, and possibly more. The designer said he would post schematic and code but the thread went cold in 2015

http://advrider.com/index.php?threads/i-wanted-a-gas-gauge.1016872/


we now return you to your regular scheduled program "Winter layup"

[OddDuck]

A few observations and thoughts from the last few weeks... I've been obsessing over the temperature control issue on inlet manifolds and carburettors (namely that there isn't any) and possible ways to build something for this.

Something that I really should have realised earlier: the famed Ducati L-twin is about the only popular motorcycle engine that has its carburettors or injectors ahead of the cylinder heads, once slipstream is considered. Inline V-twins, transverse V-twins, flat twins, inline 4's, triples, parallel twins, singles, virtually every other bike I can think of has its carburettor/s or injector/s behind the cylinder head. I.e., in the warm.

I think that there is a temperature that fuel likes to be at, before meeting air and being inhaled by the engine, and it's a bit warmer than normal NZ ambient.

At least I think that's true in my bike... crossing the Rimutaka hill, descending to Featherston and meeting sudden warm air, there was a clear transition between temperatures. The bike had been running OK, in roughly 15-ish ambient. Not great, but OK. Then we rode into air at nearly 25 degrees and quite suddenly the bike ran super smooth, then continued to do that for the remainder of the ride.

Tonight I took the bike into town and back. It's cool outside, not cold, but on the way back it started to rain. The handlebar tingle came back on the return journey. The bike hadn't been running quite right the whole way. I tried checking the carb bowl temperature (just by hand; didn't have the imager with me) and found it cool to the touch going into town and very cool coming back. It was below ambient on both occasions.

So... it's getting late, I'm getting tired. I'll carry this on tomorrow. I'd run calculations of the heat energy needed to vaporise the fuel, but maybe it's worth also calculating how much heat is needed to raise the fuel to vaporising temperature in the first place.

[FJRider]

A few observations and thoughts from the last few weeks ...

Those changes could also be made (explained) by a change in air pressure ...

[OddDuck]

Those changes could also be made (explained) by a change in air pressure ...

That's absolutely true. I haven't been measuring all possible variables.

I did a spot of reading after your comment. Yep, atmospheric pressure - and humidity - are big variables as well. The thing is, it's a mechanical carburettor. It doesn't adapt to inlet conditions the same way that ECU and sensor controlled fuel injection could do. About the best that I can hope for is that the slow air circuit can do some compensation for a few millibars up or down.

The AFR gauge lets me know what's happening with the mixture vs external conditions.

Colder weather: mixture leans a point or two
Humidity: mixture gets richer by a point or two
Atmospheric pressure: guesswork, frankly, but less of a change than might be expected. I haven't noticed any discernable changes due to weather, and the bike's never been high enough above sea level for altitude to be a serious problem.

The engine vibration leading to handlebar tingle doesn't seem to associate with the AFR readings, but it does correlate with cold headwinds pretty tightly. Warm day, smooth motor. Cold day, rough motor, and it gets worse at speed.

The thing with the temperature of the fuel bowls... I really do think that something is going on with these running too cold. There have just been too many times it's happened.

So, calculations, starting with latent heat of evaporation, petrol to air. These results are by no means definitive, they guide decisions, nothing more. It's a whole lot easier to spend a night or two running the numbers than it is to build things that don't work. I've made lots of assumptions with these:

1) 100% volumetric efficiency at all RPM
2) throttle position is irrelevant
3) perfect air-fuel ratio
4) air density is 1.2 kg / m3
5) humidity is constant and low enough to not be important

I'm not sure how to insert a table (anyone?) so here's the result for 1000 RPM.

At 1000 RPM, 900cc engine, it's doing 16.7 RPS (revolutions per second). Air volume inhaled per second is 0.015 m3. The mass of air handled is 0.018 kg, with a corresponding 1/15th mass of petrol of 1.2 grammes. These numbers scale directly with RPM, just multiply by whatever number of thou RPM the engine is being revved to.

The heat of evaporation of petrol took some working out and I really hope I got this right... I worked off this wikipedia page: https://en.wikipedia.org/wiki/Petroleum#Latent_heat_of_vaporization

It's based on relative density, presumably relative to water, and expressed in kcal / kg. This means that in terms of power absorbed I had to link the value calculated, 265.5 kcal / kg @ 20 C, to the mass of fuel being used per second, and I had to convert calories per second to watts.

So:

1 watt = 1 joule / second

1 calorie = 4.185 joules

Again, at 1000 RPM, 1.2 g of fuel needs 0.319 kcal to evaporate, or 319 calories. The heat absorbed doing this is the number of joules per second needed, equivalent to the number of calories / 4.185.

So at 1000 RPM, at 20 C, 76 watts is needed in order to evaporate the fuel.

This number scales directly by RPM so at, say, 5000 RPM, 380 watts is needed. It sounds like a lot of energy but almost all of it will come from the intake air and a warmed-up engine.

What I haven't done yet is to run the numbers again for air at 10 C and at 30 C. I think it's worth doing. Temperature is a variable throughout most of these calculations and those two points should be enough to indicate trends.

[BMWST?]

That's absolutely true. I haven't been measuring all possible variables.

I did a spot of reading after your comment. Yep, atmospheric pressure - and humidity - are big variables as well. The thing is, it's a mechanical carburettor. It doesn't adapt to inlet conditions the same way that ECU and sensor controlled fuel injection could do. About the best that I can hope for is that the slow air circuit can do some compensation for a few millibars up or down.

The AFR gauge lets me know what's happening with the mixture vs external conditions.

Colder weather: mixture leans a point or two
Humidity: mixture gets richer by a point or two
Atmospheric pressure: guesswork, frankly, but less of a change than might be expected. I haven't noticed any discernable changes due to weather, and the bike's never been high enough above sea level for altitude to be a serious problem.

The engine vibration leading to handlebar tingle doesn't seem to associate with the AFR readings, but it does correlate with cold headwinds pretty tightly. Warm day, smooth motor. Cold day, rough motor, and it gets worse at speed.

The thing with the temperature of the fuel bowls... I really do think that something is going on with these running too cold. There have just been too many times it's happened.

So, calculations, starting with latent heat of evaporation, petrol to air. These results are by no means definitive, they guide decisions, nothing more. It's a whole lot easier to spend a night or two running the numbers than it is to build things that don't work. I've made lots of assumptions with these:

1) 100% volumetric efficiency at all RPM
2) throttle position is irrelevant
3) perfect air-fuel ratio
4) air density is 1.2 kg / m3
5) humidity is constant and low enough to not be important

I'm not sure how to insert a table (anyone?) so here's the result for 1000 RPM.

At 1000 RPM, 900cc engine, it's doing 16.7 RPS (revolutions per second). Air volume inhaled per second is 0.015 m3. The mass of air handled is 0.018 kg, with a corresponding 1/15th mass of petrol of 1.2 grammes. These numbers scale directly with RPM, just multiply by whatever number of thou RPM the engine is being revved to.

The heat of evaporation of petrol took some working out and I really hope I got this right... I worked off this wikipedia page: https://en.wikipedia.org/wiki/Petroleum#Latent_heat_of_vaporization

It's based on relative density, presumably relative to water, and expressed in kcal / kg. This means that in terms of power absorbed I had to link the value calculated, 265.5 kcal / kg @ 20 C, to the mass of fuel being used per second, and I had to convert calories per second to watts.

So:

1 watt = 1 joule / second

1 calorie = 4.185 joules

Again, at 1000 RPM, 1.2 g of fuel needs 0.319 kcal to evaporate, or 319 calories. The heat absorbed doing this is the number of joules per second needed, equivalent to the number of calories / 4.185.

So at 1000 RPM, at 20 C, 76 watts is needed in order to evaporate the fuel.

This number scales directly by RPM so at, say, 5000 RPM, 380 watts is needed. It sounds like a lot of energy but almost all of it will come from the intake air and a warmed-up engine.

What I haven't done yet is to run the numbers again for air at 10 C and at 30 C. I think it's worth doing. Temperature is a variable throughout most of these calculations and those two points should be enough to indicate trends.

there are table icons just below the font icons.The table is just set for the columns and rows required and you just type in the squares

<tbody>
1 column 1 row
2 column 1 row


1 column 2 row
2 column 2 row


1 column 3 row
2 column 3 row

</tbody>

[FJRider]

I haven't noticed any discernable changes due to weather, and the bike's never been high enough above sea level for altitude to be a serious problem.



Talk to racers that do hill climbs ... But air pressure changes are not restricted to altitude changes. ie: Hot and sunny vs cold and foggy.

Air pressure and humidity on any given day can make a huge difference in engine performance ... especially with older style carburetors.

[pete376403]

Featherston is 44 meters above sea level. Your base (garage) is I guess about 10 meters above sea level. Altitude is probably not having as much effect as temperature.

Water cooling looks so much more attractive - you could have water heated manifolds that would be maintained at a more or less constant temperature and then jet accordingly.

[Rhys]

"you could have water heated manifolds that would be maintained at a more or less constant temperature and then jet accordingly"

Ducati had an oil heater for 900-750ss the (factory) carbs for winter use as they iced badly at below 5-10c

[OddDuck]

Talk to racers that do hill climbs ... But air pressure changes are not restricted to altitude changes. ie: Hot and sunny vs cold and foggy.

Air pressure and humidity on any given day can make a huge difference in engine performance ... especially with older style carburetors.

Well... I'm not doubting you. Not at all, altitude (or pressure changes) and humidity are issues. The thing is, realistically there's not a damn thing I can do about them on the road. It isn't impossible to get into the carbs and tweak, but it isn't trivial either.

Shifting needle position: raise tank, remove battery and battery box to access carburettor top covers
Adjusting slow air screw or main air jet: seat off, raise tank, remove pod filters and inlet trumpets (this is about the easiest adjustment)
Change main jet: both side fairings off, seat off so I can raise tank and turn petcock, bowl drain off, change jet and put everything back on again
Change slow fuel jet: as above but take carburettor bowl off too.

Every tweak takes about an hour, give or take, and needs tools and working space. There are bikes out there where carburettor tweaks are relatively trivial - BMW flat twins especially - but this isn't one of them.

Temperature control of the carburettor bowls or even entire carburettor bodies is possible, though, since I have a ready source of wattage available via the electrical system and / or exhaust headers. This could be set up via rider control or automatic operation. Basically I'm trying to work on the things that I can actually change or improve.

It won't be easy to build (at all) but it can be made to adapt to changing conditions, without me having to get in and fiddle with the carburettors yet again... it's been six months of tuning and I'm over it.


Featherston is 44 meters above sea level. Your base (garage) is I guess about 10 meters above sea level. Altitude is probably not having as much effect as temperature.

Water cooling looks so much more attractive - you could have water heated manifolds that would be maintained at a more or less constant temperature and then jet accordingly.

Thanks Pete. I think the manifolds are a big issue on car engines, where there are lots of different path lengths, twists and turns... much less so on this bike. The inlet manifolds are long by bike standards but are really just aluminium pipes with a single 45 degree bend. Provided that they're warm enough from the cylinder head heat, there shouldn't be a problem.

The carburettors are a different story, though, almost none of the engine heat gets to these due to the insulators. They are forward of the cylinders in the slipstream and thus are keyed very tightly to ambient air temperature - there's no air warming from the engine, except in near standstill traffic or a tailwind. Thermal management of these really is 'cross your fingers and hope' engineering.

There's good reason for that. I've been thinking for the last three weeks trying to work out a practical, reliable system for managing carb bowl / body heat. It's not a trivial problem to solve.


"you could have water heated manifolds that would be maintained at a more or less constant temperature and then jet accordingly"

Ducati had an oil heater for 900-750ss the (factor) carbs for winter use as they iced badly at below 5-10c

Thanks Rhys - unfortunately there are two problems with this for what I'm trying to do:
1) the oil heater is for the OEM Mikunis and won't fit straight onto the Keihin FCRs;
2) it isn't controlled, as far as I'm aware. I want to get those bowls to a steady temperature regardless of engine or ambient temperatures.

Carb icing: I think it may be a factor, but I can't be sure without decent measurements.

[Kickaha]

Ducati had an oil heater for 900-750ss the (factory) carbs for winter use as they iced badly at below 5-10c
You had to buy it NZ because although it was known problem they wouldn't do it as a warranty fix



Temperature control of the carburettor bowls or even entire carburettor bodies is possible, though, since I have a ready source of wattage available via the electrical system and / or exhaust headers. This could be set up via rider control or automatic operation. Basically I'm trying to work on the things that I can actually change or improve.

1) the oil heater is for the OEM Mikunis and won't fit straight onto the Keihin FCRs;
2) it isn't controlled, as far as I'm aware. I want to get those bowls to a steady temperature regardless of engine or ambient temperatures.

Carb icing: I think it may be a factor, but I can't be sure without decent measurements.

My brother had a brand new 750SS mid nineties and it suffered the carb icing problem, his fix was to relocate the factory oil cooler to a higher position so the warm air going through the cooler went over the carbs and that was the end of the problem, simple solution

[BMWST?]

could insulating the carbs be part of the fix?

[FJRider]

Temperature control of the carburettor bowls or even entire carburettor bodies is possible, though, since I have a ready source of wattage available via the electrical system and / or exhaust headers. This could be set up via rider control or automatic operation. Basically I'm trying to work on the things that I can actually change or improve.

It won't be easy to build (at all) but it can be made to adapt to changing conditions, without me having to get in and fiddle with the carburettors yet again... it's been six months of tuning and I'm over it.


Is it possible to duct warm(er) air from close to a cylinder (or exhaust) to the carb inlets .. ?? A heat exchanger type setup on each pipe for each carb ... maybe ... ??

[FJRider]

could insulating the carbs be part of the fix?

It's the cold air passing through the carbs that is the issue. Like sitting in an insulated room (mid winter) with all the windows open ... would it be any cooler in the room if it was uninsulated .. ??

[BMWST?]

It's the cold air passing through the carbs that is the issue. Like sitting in an insulated room (mid winter) with all the windows open ... would it be any cooler in the room if it was uninsulated .. ??
yes i see 10 char

[OddDuck]

My brother had a brand new 750SS mid nineties and it suffered the carb icing problem, his fix was to relocate the factory oil cooler to a higher position so the warm air going through the cooler went over the carbs and that was the end of the problem, simple solution

Now that's an idea - it'll get the oil cooler out of the firing line of stones etc too. I like it.

[OddDuck]

Is it possible to duct warm(er) air from close to a cylinder (or exhaust) to the carb inlets .. ?? A heat exchanger type setup on each pipe for each carb ... maybe ... ??

Yeah, that was the original idea until I read Kickaha's post.

It's done a lot in the car world, or was, before injection. The heat exchanger is known as a heat stove, it's about the most basic exchanger imaginable - just a box with an open bottom sitting over the exhaust pipe, with a duct running upwards to an inlet manifold above.

Sometimes there's a butterfly valve activated by a bimetallic spring. Once the spring warms up it closes the valve, the engine now warm and the heat stove not needed any more.

The issue/s I face with the ducati make this solution quite hard to implement - this isn't happening under a hood, there's slipstream. I'd have to insulate the ducts going upward, I'd also have to sort out air flow. Finally I'd have to arrange temperature control via the butterfly valve, with the valve close to the heat stove and the sensor close to the carbies.

It's a whole lot easier to just relocate the oil cooler...

[OddDuck]

Made a discovery today - I think (concerning the issue of carb icing) that the FCR41's have a fairly serious design issue. There's an adaptor connecting carburettor throat to insulating rubbers and then inlet manifolds, this adaptor screws into the carb body.

I've just scanned the thing with the thermal imager, shortly after cold-starting the bike and running for a few minutes. The adaptor is the narrow black band in the image. It's running at between 3 to 5 degrees below ambient, at least, the fragments of PTFE tape on the outside of the thing are. It'll be colder inside of course. It's also a few degrees colder than the carburettor body itself.

This adaptor is precisely where the icing problem is likely to happen - in the immediate fuel-air mixing area just after the venturi, needle and jets. It doesn't have a high thermal mass or a particularly good connection to ambient temperature. There's the thread to the carb bodies, but that's it. Experience has shown that any metal-to-metal contact interface presents a heat flow barrier, i.e. tends to make a thermal insulator. If you want heat to transfer, it's either solid metal or conductive heat sink paste.

I'd assembled this with PTFE tape, wanting both to air-seal the thing in such a way that it could be unscrewed again, and wanting something that the petrol wouldn't slowly dissolve. Unfortunately the PTFE is a pretty good thermal insulator, even over the tiny thicknesses inside a thread.

Right... I'm going to have to either use a thermal epoxy and permanently attach the adaptors, or find a heatsink compound that can tolerate petrol long term. In either case, whatever's used is going to have to tolerate the full engine heat convecting up through the manifolds on shutdowns - the carburettors get quite hot after the bike's parked up. I'll have to properly check what this temperature is.

[OddDuck]

Took the bike for a run into town and back, then had a go at measuring how hot the carbs could get with updraft from a hot engine - most of this will happen due to convection inside inlet manifolds, not rising air around the engine. The pictures say most of it - appears that the carbies reliably don't get hotter than 30 degrees on a winter's day, maybe 50-ish in the middle of summer. I remember touch-testing this much earlier and was quite surprised at how hot the carbs can get after a minute or two parked up.

Quick notes:

Shiny metal is a bad target. The rubber insulating boot was used as a datum because the rubber 'shows' the heat well... the manifold right beside it will be at the same temperature but it's reflecting the surroundings instead of radiating its own heat.

Oxidised cap screw heads are a good target. There's a cavity, which helps, and the oxide layer is a crappy reflector, which means it's a good heat emitter.

The carb bodies are a bit too shiny to really be a good target. I've tried to shoot corners or cavities, rather than flat metal surfaces. The quick test for target surfaces with a thermal imager is to see if they act like a mirror: get something hot at the right angle that its image would bounce to the imager, then see if it shows up. If it doesn't, it's a good surface to read a temperature off.

The screw-in carb body to rubber insulating boot adaptor briefly became hotter than the carb body, demonstrating the thermal separation between the two.

[OddDuck]

First steps on a couple of things.

1) Fitting the electronics to drive the carburettor bowl heaters. The little thermostat needs an on-off switch, a fuse, and weather protection. This was a bit of an exercise in just buying an enclosure and trying it for fit, to both the bike and the components mounting on it or in it. It was only $3.50 out of Jaycar, it's not the end of the world if I have to go back for the next size up or down.

It'll go onto the bike. There's a place where it can be tucked out of view inside the side fairing, mounted on the instrument sub-frame side rail, but accessible to a gloved hand for switching on or off.

In this setup, I won't be able to see the relay indicator, the digital display, or access the setpoint buttons. That isn't really a problem though... I'll set operating temperature once, then never worry about it again. All I really need to know is how long to run the heaters before hitting the starter button.

2) fitting the heaters and temperature sensor to the carburettor bowls. Should be easy, could be easy, so far it's fighting me. I tried making a clamp-on metal block, but it's clunky at best and it won't transmit heat well without thermal adhesive or similar. I'll revert to sticking the heaters in the idle mix adjust screw holes, with provision for easy removal, and find a place to fit the sensor. Somehow.

3) thermal adhesive. This stuff might make life a bit easier: it's two-part epoxy, but with thermal conductivity like heatsink paste.

The stuff I've ordered is supported by its parent company with online datasheets, including good info like glass transition temperature, service temperature limits, and susceptibility to solvents like petrol. So far it checks out... here's the page:

https://www.atomadhesives.com/AA-SUPERTHERM-195-Thermally-Conductive-Epoxy-Adhesive

I ordered a pack through Amazon. It's a pain having to wait, but I'd tried local supply (Jaycar) and all they had was thermal plaster. I don't think it'll survive. Vibration, heat, thermal expansion, and petrol don't make an easy environment for this stuff.

[OddDuck]

I finally took a few hours and went through the numbers on latent heat of vaporisation for various different temperatures. Assumptions:

5000 RPM
100% volumetric efficiency
Throttle position doesn't matter
Petrol's relative density at 20 C is 0.72 (relative to water)
Petrol's change in mass is 0.7 g / litre degree C
Humidity irrelevant for this.

So, the equation for heat of vaporisation sums up as:

L = 1/d x (194.4 - 0.162 x T)

where

L = heat of vaporisation, in kcal / kg
d = relative density, dimensionless
T = temperature, degrees C.

The density of petrol changes with temperature of course. If we start with petrol @ 20 C, then:

5 C: 730.5 kg / m3
10 C: 727 kg / m3
20 C: 720 kg / m3
30 C: 713 kg / m3

So, factoring that density change into the heat of vaporisation, and working out L:

5 C: 265 kcal / kg
10 C: 265.2 kcal / kg
20 C: 265.5 kcal / kg
30 C: 265.8 kcal / kg

Basically the heat of vaporisation is insensitive to temperature. This was a surprise, but maybe that's why petrol is widely used as a fuel, it's forgiving to work with.

Anyway, carrying on to work out heat absorbed from vaporisation. I assumed that tuning had been set at 20 C, with a 1:15 fuel-air ratio, and that the volume of fuel subsequently was constant against temperature. The density of fuel, like the density of air, would change with temperature, hence ratio changes due to temperature. 5000 RPM, 900 cc, 1 atm, 100% volumetric efficiency... here's my first go at a table:



Temperature (C)
5
10
20
30


Density Air kg/m3
1.269
1.247
1.204
1.165


Mass Air (g)
95.175
93.525
90.300
87.375


Mass Fuel (g)
6.11
6.08
6.02
5.96


L kcal/kg
265.0
265.2
265.5
265.8


Heat Absorbed (Watts)
386.9
385.3
382.0
378.5



So the wattage required to evaporate the fuel does increase slightly as things get colder, but it's not a big change.

At this point I realised something... before the fuel can evaporate, it has to be brought to evaporation temperature. Whatever that is. There's a range of volatiles in petrol and as such there's a wide band of boiling points. These are also affected by pressure.

An issue with volatiles like petrol is something called partial pressures. A bit of petrol, at almost any practical temperature / pressure, will evaporate until equilibrium is reached between vapour and liquid. I've decided in the interests of sanity to ignore this, assuming flow rates through the carburettors are high enough that bulk evaporation only needs to be addressed. The other issue is the pressure drop in the carburettor bowl. It'll be running below 1 atm in there, and that means the boiling point is lowered.

So... further big assumption... petrol (generally) starts evaporating at 38 C and reaches final boiling point at 205 C, at 1 atm pressure. I'll assume that an ideal base temperature for petrol to be at, in the carb bowl, is 30 C.

Droplets sprayed cold into incoming air will have to be raised to 30 C before they can evaporate. This heating will happen under compression, even in a cold engine. The incoming air charge will get heated purely by compressing it. However it will take time, not all the fuel will convert to vapour, combustion will be messy at best... what if the fuel is preheated, prior to the carburettor, and what wattage is needed to do that?

For the same set of conditions as above:

5 C: 337 watts
10 C: 270 watts
20 C: 135 watts
30 C: nil, it's already there

I don't think that this will affect carburettor icing, though. That's purely down to water vapour, air temperature, lowered pressure through the carb venturi, and the heat of evaporation of petrol. It's a widely known issue in light aviation, with a lot of charts available showing icing conditions and when to apply carb heat. It looks like heating the entire carburettor is on the only way to solve icing. If anything, pre-heating inlet fuel but leaving the carb cold might actually make icing worse, since the petrol will evaporate closer to the carb throat instead of staying in droplet form further down the inlet manifold.

Pre-heating inlet fuel... I think any advantage here is in engine starting and cold-engine rideability. It's going to adversely affect carburettor tuning vs temperature, by reducing density of the fuel against cold air, and there may be issues with reducing internal cooling in the cylinder and head during the induction / compression strokes. I'll have to do some further reading and see what's already been done.

[OddDuck]

I had a couple of orders arrive, concerning tools for work on the valve shims.

The first was this odd set of plastic pliers:

http://www.regal.co.nz/category.php?sub_id=663

The idea was that they're non-marking and they lock. Ideally I'd like rubber-jawed, adjustable position vicegrips with a 45 degree gooseneck in the jaws, with a slender nose as well... but nobody makes these. Fine. We'll give these a go.

They do actually work - perhaps better with some heatshrink over the jaws so that they grip better - but once filed at an angle, they'll hold the valve stem without damaging the valve guide seal. They don't hold particularly strongly so there may be a couple of repositions and haulings up of the valve, however it's a lot better than mechanic's magnetic pick-up tools and lots of fiddling. Or cable ties and side cutters with bits of loose plastic pinging around, if I don't cut the seals into the bargain.

The second item was this:

http://emsduc.com/product/rocker-holder-tool-2v-7mm/

I saw the photographs and thought I could knock this up in half an hour out of a piece of barstock. Then I bought it anyway. I'm glad I did, this wee tool is a gem and I sincerely wish I had this years ago.

It does raise questions though... is there a difference in shim clearance measurements when bodging with a screwdriver vs using this?

This thing is highly controllable. It's easy to feel the slack in the closer arm and it's easy to be consistent. That can't be said for jabbing with a screwdriver. I also found that the valve clearance measurements I took at the last service interval were questionable to the point where the replacement shims I had also ordered weren't of use.

Replacement closer shims caused engine lockups (this is why we always turn the engine over by hand with an engine rotation tool, straight off the crankshaft), and replacement opener shims were simply too large and would have left the valve off its seat. Something's going on. Hmm. For now I've put covers back on and left the engine as is; I'll check again at the next 3,000 mile interval.

[OddDuck]

The reason it's been so quiet on this thread over the last week or so is me trying to actually concept, design, and make the attachments needed for the cold-start system. It's been fairly involved.

Quick recap: I think that pre-heating the petrol, directly in the carburettor bowl, is a valid alternative to a choke for enrichening the mixture during cold starting.

The trouble is getting a heating element into place and then controlling it. We really don't want to boil the petrol off or worse, damage rubber seals. The carb bowl, as is, doesn't give many options for placement of either heater or temperature sensor. After several full nights considering what to do, I finally decided to bolt an attachment plate on, carrying the temperature sensor for the control thermostat, and providing mechanical retention of the heater element itself. This was to be one of the 40 W cartridge heaters (from the 3D plastic printing industry), directly inserted into the bowl well for the idle mixture adjustment screw.

The heater had to go straight into the carb bowl, somehow. Heating a clamp-on plate up was simply never going to work; the interface between two different bits of metal was always going to be too much of a heat barrier. This oval 6x7 well was the only place suitable for the heater.

So, holding the heater on... I thought about wire clips, springs etc, and finally realised that the only solution that I can count on is a bolted-on plate, supporting the heater from below. There's simply too much vibration for anything else to work.

It's the same for the sensor. It's got to be secured. Glue, spring clips, clamps etc will fail, after a while. It's got to be bulletproof. The last thing I want to be doing is breaking tools out while on tour.

I'd like to model and cast a replacement carburettor bowl, carrying re-entrant wells for both heater and sensor, these re-entrant wells carrying circlip grooves or similar. Failing that, I'd like to machine bowls up out of billet. Neither is an option right now unfortunately, so a bolt-on plate it is... this can be done with suitable plate stock metal, a drill press, a bench vise, and hand tools. You don't need a foundry, dedicated moulds, or CNC machine tools to make this happen.

So, I got the carburettor bowls off the bike, got the verniers out, measured up, and had the first go at it. I'll quickly mention methods, in case this is useful for someone else out there.

Marking out was done by drafting up in a CAD/CAM program and printing out at 1:1 scale, then sticking the printout directly to the metal with double-sided tape. This lets me quickly centerpunch holes without fiddling with ruler and set square, also it keeps a limit on inaccuracies. This isn't better than +/- 0.25 mm, but for this it doesn't have to be.

Drilling the big 20mm holes needed to clear the carburettor bowl drains was done with a step drill. These are normally intended for sheet metal or plastic; in this case, I went straight though 6mm plate with a 4-12, then a 10-20 mm step drill in one setup under the drill press. It actually works if swarf is cleared and lots of cutting fluid is used. The final 20mm diameter is best done by slightly extending the drill in the chuck, not (as I did) turning the work over.

Cutting slots was done by drilling a hole and then filing with a chainsaw file. These are great little things - constant diameter round files. I've found them much more useful than standard, tapered round files.

Cutting from the plate itself: I'd centerpunched the outlines, so after the printout failed under cutting fluid and abuse, I still had the outline to work to. This was simple work with hacksaw and file.

Fitting the plate to the carburettors: in the electronics industry, they use a lot of PCB spacers. These are useful fasteners for this kind of work. It turns out that if I have 14mm spacers at the rear, 32mm spacers at the front, then I'm on the same plane as the machined flat carrying the carburettor bowl drain. These spacers had to be cut to length and then squared up. Lacking a lathe (I'd really like one someday) a makeshift technique is to roughly length them with a hacksaw, fit them into a drill and present them to a grinding wheel, square on. This trues them up and lengths them quite nicely and controllably, albeit with a few stop-starts and checks with verniers.

The sensor retainer plate: this was drilled locked into the master plate. No tool more sophisticated than a manual drill press was needed. That said, these retainers are individual to their master plates, they're not interchangeable.

I have no idea yet if all this actually works. I'll have to remove the carburettors from the bike and get them onto the bench to test fit, file holes, and fit properly... or redesign and remake where necessary.

[pete376403]

If Bert Munro rode a Ducati, this is how he would have done it.

Files, hand drills and the odd thermal camera.

[OddDuck]

"blush"

High praise indeed. Haven't been trying to file camshafts out of tractor axles yet though...

I did Gold Ride Forever on the weekend, then took Anzac Day to go out and have a first try at practising some new skills.

I've been learning to ride ad hoc. It took doing a course to really highlight the gaps in what I'm doing; it's very difficult to see what's missing. The old saying about getting to a level and then staying there has applied for some time and it's good to make progress.

Highlights (for me):

- Trail braking (already proved its worth in a tight corner)
- Using rear brake only when at low speed, pulling up, parking etc
- Looking through corners to the vanishing point, eyes up and on the horizon
- Corner to the longest possible visibility instead of race apexing
- Clutchless shifting. This probably wasn't part of the course, it sort of happened incidentally... for me this was huge. I've heard about it but it wasn't until someone else was doing it in front of me that it 'clicked', so to speak.

That's a fraction of what was covered. It was a good day out, so was the day of trying to ride in a new way.

[Voltaire]

"blush"

High praise indeed. Haven't been trying to file camshafts out of tractor axles yet though...

I did Gold Ride Forever on the weekend, then took Anzac Day to go out and have a first try at practising some new skills.

I've been learning to ride ad hoc. It took doing a course to really highlight the gaps in what I'm doing; it's very difficult to see what's missing. The old saying about getting to a level and then staying there has applied for some time and it's good to make progress.

Highlights (for me):

- Trail braking (already proved its worth in a tight corner)
- Using rear brake only when at low speed, pulling up, parking etc
- Looking through corners to the vanishing point, eyes up and on the horizon
- Corner to the longest possible visibility instead of race apexing
- Clutchless shifting. This probably wasn't part of the course, it sort of happened incidentally... for me this was huge. I've heard about it but it wasn't until someone else was doing it in front of me that it 'clicked', so to speak.

That's a fraction of what was covered. It was a good day out, so was the day of trying to ride in a new way.

Out of interest what are the benefits of clutchless gearchanges?
I know they do it on racetracks but I've never been keen on my airhead BMW racer having seen the inside of them.
Its enough for me locking the rear dropping into second...
Only time I ever used it was when the clutch cable broke and had to sync the gears before easing the lever thru.

[jafagsx250]

It's faster at the drags but off the top of my head there doesn't seem to be that many benefits

Sent from my GT-I9506 using Tapatalk

[OddDuck]

Yep agreed, way faster at the drags (and presumably blipping down while approaching corners). It's a valuable track skill. No wonder track riders will buy quickshift kits.

In terms of safety, about the only justification I can see is minimising the time that the engine isn't engaged with the rear wheel. The fastest that I can do a clutched shift is maybe half a second, and that's risking skidding the back wheel if I'm engine braking. Clutchless, if done right, there'd be potential for a false neutral for a fraction of that time.

Unfortunately (speaking authoritatively here after one day's riding practice) you've got to get the matching between rear wheel and engine right otherwise the gearbox locks and won't shift. In a panic situation it might be very easy to get locked into the wrong gear.

The other use I can see for learning this skill is in the case of a stuffed clutch actuator. Maybe the bike's had a fall and broken the lever off, maybe the hose or cable has failed, or the seals on the slave piston have gone... you might have to get a bike home without much in the way of clutch usage.

I'll keep practicing and see. In the meantime I want to read up on what this does to the lifetime of a gearbox - I made some pretty choppy changes yesterday and had the bike lurching or diving a couple of times, that sort of thing can't be good.

[jafagsx250]

I am pretty curious about how bad downshift are clutch less. It doesn't seem so bad up shifting but I pretty much always use the clutch to down shift.

Sent from my GT-I9506 using Tapatalk

[OddDuck]

I had less trouble with downshifting than going up. A little blip on the throttle, shift, done.

Seems the trick is to get the torque transmitted to the rear wheel as close to zero as possible. Early days yet though.

[Voltaire]

I did a Honda riding school once in the UK and I remember one line " use the brakes for slowing down not the gearbox as brake pads are cheap to replace

gearboxes less so"

I can see the benefit of any time saving ideas when racing but when you have to dismantle your Bevel Drive Ducati because it jumps out of 1st dues to worn dogs

you tend to use the clutch. Modern gearboxes are probably stronger.

My stock carbs on the 900 SL are leaking, where do I get that float and valve assembly from locally?

You mentioned BMW airheads earlier....far easier to do the carbs on them :rolleyes:

[OddDuck]

Apologies for the delay in replying.

Stock carbs bits are easy - dealer network or online through Stein Dinse. I'd go dealer network if possible, I had bits ex Aus in about a week when I replaced emulsion tubes.

[OddDuck]

Finally had a moment to get back into it, with several issues wanting attention. Last night I had a look at the weak front headlight - these bikes are notorious for dim lights.

It's been like this since I've had it. It's been liveable until a recent ride involved crossing the Rimutaka Hill after dark. Late, tired, oncoming cars with dazzling headlights... not good. The headlight's actually OK if my eyes have adjusted to it, the issue is how bright everyone else's lights have become.

The first thing I tried was changing the bulb for something billed as 30% brighter. The two photos of the bike lighting up the garage door are before and after, with the camera shooting on full manual and the exact same exposure settings in terms of shutter and aperture - in short you can see the difference.

There is actually 30% more light. That shows up on the exposure histogram. The trouble is that it doesn't look like much at all to the eye; cameras see light in terms of double or half and I think the human eye works on similar scales.

Much earlier I'd measured voltage at the headlight bulb and found it wanting. Not re-measuring (I should have) I took the handlebar switch block off, with a view to getting into the contacts and giving them a clean. Basically, for anyone else out there contemplating this, the headlight / indicator / high beam switch block isn't serviceable, as far as I can tell. It's snap-together construction which doesn't come apart again. Some of the plastic seemed to have the beginnings of cracking, so I decided not to risk forcing anything.

It also seems to have been designed right. The photos don't show this as clearly as I'd like, but a couple of the contacts for the headlight are visible in one frame, covered by the switch mechanism in the next. These are sliding contacts, not press-togethers. They get wiped clean every time the switch is used.

The logical next step to take would be to trace wiring and check contact resistances via multimeter, but the connector block showed clear traces of corrosion on some of the pins. To my mind, that's far more likely to be a problem. Metal oxide is a very good electrical insulator, even in thicknesses of microns. The check is to get some dielectric grease (not conductive, not inside a multipole connector block) and make-and-break the connector a few times to wipe the pins, then try the headlight again.

A last note about checking resistances with a multimeter... I'd read somewhere that the only real check in a wiring loom is to power it up and measure voltage drops across runs of wire, across switches or connectors, etc. The reason for this is current: under power, the headlight draws 55 / 60 watts, at 12V. That's 4.6 amps under normal loading. A multimeter's sensing current for ohms would be in the milliamps. A thread of metal holding a wire together might test alright, under milliamps; it'd be a very different story under nearly 5 amps.

The amperage also highlights any defects in connectors. There's heat damage on one pin of the old headlight bulb. I'll have to get the thermal imager out again and have a look at this connector, with the headlight running.

[OddDuck]

Had a look with the thermal imager tonight, after reassembling the switch block to the bike and pulling the headlight assembly off the front so that terminal connections to the rear of the main bulb could be seen.

A couple of surprises followed. The bulb itself is the main heat source, the terminal and wiring was fine... and there's a pretty obvious hotspot at the main fuses. The wiring's possibly undersized, but it's very clear that there's a high resistance spot at the push-on connectors to the two main fuses. The confusing photo of the wires is of the fuse box underside, showing the leads into the fuses. There are two shots, one with main headlight on, one with the headlight off - the second pair of wires are running cooler with the headlight off.

I tried pulling the 15A fuse and having a look at the blades - one was a bit oxidised, but nothing too bad. The headlight switch and switch block connector didn't show up as anything special on the thermal imager, although I didn't run the ignition for long - the AFR sensor doesn't like being powered up with the engine off for too long.

I re-shot the headlight with the same camera settings as before, a quick test to see if fiddling with fuses or the block connector had helped. It had, a very little, but it's not significant enough to be definite.

[pete376403]

Does the headlight run via a relay? Run good sized cables from the battery to the relay and light and all the wimpy contacts in the switchblock have to do is power the relay coil.



Or go to Pick-a-part and find HID lights and power supplies - if you can find one that would fit in your headlight (square IIRC)

[Voltaire]

/\ /\ wot he said about the relays.

Ducati wiring is undersized and the earths are not great.

I fitted an LED to my old H4 BMW but the cut off for low beam is not that great.

Don't get brightness confused with colour, as different lights work on different spectrums.

Rewiring my Commando at the moment, all new electrics other than the switchgear which I'm only using to operate relays.

HID is not legal unless factory fitted AFAIK.

[OddDuck]

Yep, what Pete said. It's the way to go. Just because I'm curious I went and had a trace through the wiring diagram.

The OEM ducati wiring loom has the following steps for the current to the headlight to take:

Battery terminal
Terminal block
30A fuse
Main relay
15A fuse
Terminal block
Headlight slide switch
High / low switch
High / low beam filaments
Headlight earth

Along the way there are also eight push-on crimp connectors for either high or low beams. The wiring for high beam uses two conductors running parallel, low beam just one - the wire is 2mm OD, including insulation. Throw in twenty years weathering and general degradation of wiring and contact points and no wonder it's struggling.

The use of relays would mean that high current would run:
Battery terminal
Dedicated fuse
Relay contacts
Headlight filament
Earth

There'd be six push-on crimp connectors and no terminal blocks. I could check the chosen wiring via thermal imager to make sure I'm not losing voltage due to light-duty cables.

Using relays will mean installing two, one for high beam, one for low, plus a fuse each. It'll be worth it I think... here's a copy-paste from Wikipedia:

Tungsten halogen lamps behave in a similar manner to other incandescent lamps when run on a different voltage. However the light output is reported as proportional to V to the power of 3 (i.e cubed), and the luminous efficacy proportional to V to the power of 1.3. The normal relationship regarding the lifetime is that it is proportional to V to the power of -14. For example, a bulb operated at 5% higher than its design voltage would produce about 15% more light, and the luminous efficacy would be about 6.5% higher, but would be expected to have only half the rated life.

Light output proportional to V cubed.

Playing with numbers again... let's say nominal voltage is 12V. What voltage drop does it take for light output to halve?

12 x 12 x 12 = 1,728

1,728 / 2 = 864

Cube root of 864 is 9.52 V.

In short, drop 2.5 V in bad wiring and that isn't roughly a fifth of the light intensity gone, it's halved.

Edit: I've bought some heavy-gauge automotive cable (Jaycar's off shelf offerings seems both higher quality and cheaper than Supercheap Auto) and had a play... early days yet but I reckon the way to size high current cabling is to build a system, measure voltage drops, decide to rebuild if needed. It looks like the commonly available wire size charts are written with sizes chosen against burnouts and catastrophic failures, not the ability to carry current without significant voltage drops.

[OddDuck]

First go at fitting the cold-start system to the carburettor bowls.

I had to shorten a few of the pcb spacers. Before shortening, I used the existing threads as a guide for drilling and tapping, making sure there'd be enough thread for the cap screws. This left fine swarf in a blind hole, which is a pain - it'll jam up and lodge in threads if I try running a bolt in without clearing it. Blowing swarf out with the CRC worked though, a run-in of a cotton bud finished it off. I photo'd this the same way I did it, but I recommend gloves. Something in the CRC soaked into my skin, and I wouldn't do it this way twice.

There was a fair bit of filing to get the plates to bolt on. I had a few parallax errors with my original measurements. It looks like I'll have to put the heater retaining holes through a mill, as well - these need to be slots instead of holes. I want the heater elements to sit properly against one side of the carb bowl re-entry well, instead of skewed in the hole, and for that to happen the control surface has to be that well. It can't be the plate underneath.

Getting closer to testing... The orange tape on the carb bowl is there as a decent target for the thermal imager. I want to compare bowl temperature to what the thermostat contact probe reads.

[OddDuck]

Finally got around to something I've been wanting to do for a while - use thermally conductive epoxy on the threaded adaptors that the Keihin FCR41's use to connect to the inlet manifold rubber boots. The glue, courtesy of Atom Adhesives and Amazon, had arrived three weeks ago but I'd wanted a completely clear day to get stuck in to this particular job.

Doing this means that the adaptors are now connected permanently. That's fine; they've been on for years and there's been no service reason to take them off again.

The carburettors came off the bike reasonably quickly. I used earplugs (I like the 3M foam disposables, for some reason) on the fuel lines to stop gasoline splashing everywhere - wish I'd thought of this trick earlier. It saved a lot of mess. Once the carbs were on the bench, it was easy to put the fuel lines into a can and tip-tilt the carb bodies to drain fuel from the bowls.

Once off, it was a surprise to find both threaded adaptors were actually loose. Not rattle-loose, but close. Unscrewing the adaptors revealed beat-up remainders of PTFE tape in the threads and ingrained dirt, presumably pulled in under vacuum leakage. Not good, but it does provide some hints as to why the AFR reading has been doing some strange things at 1/8th throttle. There's been a serious hole in the mixture strength under sustained running at that throttle setting. This PTFE thread was continuous when I'd last assembled the adaptors so clearly it's degraded significantly over time and usage.

Cleaning time, pre epoxying. I scrubbed threads with an old toothbrush and methylated spirits (this takes dirt off without leaving a film behind on the surface, at least as far as I can see). Some of the dirt proved quite resilient and had to be taken out with the point of a knife, then I worked out a way to push the brush bristles onto the threads so that the bristle points were leading instead of trailing, trying to lift dirt out instead of brushing it deeper. Scrub, wipe with rag to try to transfer dirt into the matrix of the fabric, scrub again... got there in about an hour. I get one shot at this epoxying and I'd really like clean metal surfaces for this.

[OddDuck]

Right, time for an entire post about using epoxy to glue two carburettor adaptors in.

Basically, the thermal conduction part of this wonderstuff depends on contact area. It won't work as planned if it isn't over the entire surface area. Accordingly I had a couple of goes at this. It's slow-drying epoxy and is rated as workable for 60 minutes after mixing.

First try: carefully paint the adaptor threads, screw in, remove to check penetration and filling. Err... Nope. There was epoxy on the first few threads and then after that the metal had been wiped.

Second try: carefully paint adaptor (male) threads, then do the same to the carburettor body (female) threads. I used dabs of epoxy onto the blade of a flat screwdriver for this. The idea was that if epoxy is wiped off the back of the threads by the screwing-in action, it'll also be pushed forward as well, filling up the gap at the adaptor nose and demonstrating filling by beading out on the internal join as the adaptor is screwed home. The threads themselves should remain submerged, albeit with an air bubble or two.

This worked, as far as I can tell. Beading happened on both the inside and outside of the adaptors. Internal beading was very carefully wiped with single passes of a rag (use once, fold over, use again, fold again, etc), starting with the carburettor slide and then moving to the body wall and outwards. I was very careful to avoid pushing epoxy into the slow jet opening or the slide gate. External beading was cleaned up relatively easily with a folded rag, wiped around the perimeter.

The epoxy is rated at achieving 100% bond strength at 24 hours, if 20 C is maintained. Tonight will get colder than that, but I should be good to replace the carburettor bodies tomorrow night. I don't want to take the chance earlier, although it's solidified already.

[OddDuck]

Since the carburettors are on the bench and are accessible, I took a few minutes to fit the cold-start heaters and thermostat sensors.

The little tabbed bits of metal are bits of shim, cut with tinsnips and used as springs, to keep heater elements pressed up against one half-round of the elliptical bowl well (it's 6mm by 7mm).

No heatsink paste or thermal adhesive was used. The slow fuel jet screw is above this heater and I want to keep access, without breaking things or gooey heatsink paste going everywhere, every time I need to make an adjustment.

I've got provision for two sensors. At the moment the plan is to run one thermostat, driving both heaters in parallel, and assuming identical behaviour between carburettor bowls. This leaves the other sensor free for use as a monitor, or for some other temperature control arrangement.

[OddDuck]

Well, I've spent a frustrating week trying to source replacement oil cooler hoses for the cooler shift (online only so far, I'll scout the shops shortly).

I need -6 AN hoses:

hose 1 with one end straight, one end 90 deg, 450mm length
hose 2 with one end 45, other end 90, these are cross-plane and need to be rotatable, 500mm length

I've tried placing an order with these guys:

www.improvedracing.com

Lots of goodies. Unfortunately they've come back with a two-week delay due to waiting on parts.

Can anyone suggest a supplier local to Lower Hutt with walk-in service?

[Ocean1]

Well, I've spent a frustrating week trying to source replacement oil cooler hoses for the cooler shift (online only so far, I'll scout the shops shortly).

I need -6 AN hoses:

hose 1 with one end straight, one end 90 deg, 450mm length
hose 2 with one end 45, other end 90, these are cross-plane and need to be rotatable, 500mm length

I've tried placing an order with these guys:

www.improvedracing.com

Lots of goodies. Unfortunately they've come back with a two-week delay due to waiting on parts.

Can anyone suggest a supplier local to Lower Hutt with walk-in service?

Made to order is going to be a lot more expensive. But try Pirtek out in Porirua: http://www.pirtek.co.nz/pirtek-service-centre/?store_id=1505

Ring first, he's often out on a job. And I'm not sure he'll have access to rotatable ends...

[OddDuck]

Thanks Ocean1 - I've kept the order alive with the US supplier, mostly because the price is pretty reasonable for a pair of one-offs.

By chance I bumped across this seller on Trademe:

http://www.trademe.co.nz/Members/Listings.aspx?member=2307520

Lots of -AN oil cooler hose stuff for sale but it looks like he only lists ads sometimes. Hose, fittings, finishers etc. The advantage of going this way - DIY assembly - would be that hoses could be fitted to assemblies in progress, there wouldn't be any taking measurements and hoping that hoses fit when they turn up.

Anyway... slow progress on things electrical over the last few weeks. I've been having to learn the basics concerning auto wiring looms, my experience previous being bench mount / indoors stuff.

The first go at the controller's box for the carb bowl heaters didn't go so well. A few hours drilling, filing and fitting for various components, then I tried making permanent connections and promptly stuffed the switch. Soldering was fiddly, slow, melty (box and wire insulation), and finally it damaged the switch's rocker mechanism.

Previously I've been spoilt with switches made with bodies moulded in epoxy resin or similar. Even with push-on terminals, soldering is possible. Not so here; this particular impact-resistant plastic has a low melting or flow point and any hot work on the terminals is a bad idea.

Also, goodies didn't fit into the box. It's one thing to jig everything up on the bench and think, yeah, it'll be a bit cramped but I should be able to stuff it all in. Nope. Once the wiring starts going in, available space starts disappearing fast, then the roadblocks start appearing.

So, second try, using experience from the first go to redesign where necessary. The pictures say most of it. Work was sped up greatly by going from cordless hand drill to a drill press, using a step drill (for the 11mm holes needed for the short rubber grommets), and going to crimp connectors or clamp terminals throughout.

This was fired up today to check heating and control. Start temperature was 12 C, setpoint 27 C. This was achieved in around 1 minute, about the time I'd want to get helmet and gloves on, although I didn't time it. I did try starting without much luck, but the bike's been sitting for nearly three weeks now and the petrol isn't the best any more.

[OddDuck]

I increased the setpoint to 39 C and tried again. Much improved; even with stale petrol, the bike caught in a few cranks and held idle with the throttle lightly opened. It did take a couple of minutes to get to that temperature, though.

Got the headlights sorted today as well, finally. The relays and 25A-rated cable did the trick. The photo of the bike lighting up the garage door doesn't look different to previous - maybe worse, given that the wide spread of light seems to have disappeared - but the camera exposure has changed significantly.

Before relays: iso 500, 1.6 seconds, f/8.
After relays: iso 500, 0.3 seconds, f/8.

It's a far cry from a lightmeter measurement but as an indication it's pretty clear: light levels have at least doubled. Before I fitted the relays, I tried measuring voltage dropped in the loom with the old setup. Voltmeter A is checking battery voltage - roughly 11.5 V during test, with engine off - and voltmeter B is checking voltage at the bulb terminals - roughly 8.7 volts during test.

The OEM loom is dropping nearly 3 V. No wonder these bikes have a reputation for dim headlights.

A few notes about the relays installation, for anyone else contemplating a similar mod...

I used flyback diodes. These are arranged with the stripe toward the voltage signal line, i.e. blocking current when voltage is applied normally. Flyback, more commonly known as kickback, is the situation where supply voltage is suddenly switched off an energised coil. The coil attempts to maintain its field, so it fires a kickback voltage back into its circuit while the magnetic field is slowly collapsing. This voltage can be very high - a couple of hundred volts, even from these little relays - and if there are any semiconductors around, the spike can fry them. The same effect is used in ignition systems to drive a spark plug. The kickback diodes allow a reverse polarity current to run through the coil, safely dissipating the energy.

Probably I didn't need the diodes - automotive looms are supposed to be low impedance, with lots of leakage and stray capacitance to suppress voltage spikes - but if anything will be hurt by using them, it'll be the relay coils. These are a lot more replaceable than anything else on the wiring loom like switch contacts, the Rec-Reg unit, or my wideband AFR gauge, so flyback diodes it is.

The relays carry little 15A fuses on the high-current lines. This is very convenient, I don't have to install a fusebox somewhere or connect in-line fuse holders.

The relay sockets don't latch. I've resorted to strapping them onto the relays with cable ties. I really don't want these dropping off the relays during a ride.

The headlamp terminals are 8 x 0.8 mm spade lugs. I had to order these off Radiospares, not having any luck at Jaycar or Supercheap Auto. Maybe Repco do something, or someone knows an auto electrical supply specialist.

I had to branch the high-current lines - one relay for low beam, the other for high beam. This turned out to be more wire than a yellow butt crimp connector could fit, so I improvised a pair of crimps out of the flashing from the spade lugs and insulated with heatshrink.

The other note is about the polarity of the coils on the relays themselves. The convention is that positive goes to terminal 86, ground to terminal 85. This caught me out: the little diagram on the relay has 86 under 85, and every DC circuit diagram I've ever seen has positive voltage above ground, not below it. In theory it shouldn't matter. The coil isn't polarised, unless you've got a relay with a kickback diode already installed inside it.

Anyway, I've got the fairings back on, I want to test ride the engine to see what effect the thermal epoxy had on the carburettor adaptor tubes before making any other changes.

[OddDuck]

Took the bike out for a quick ride, ambient temperature cool but not cold - say around 12 C.

Cold start electric heater: worked a treat. No sustained cranking, no restarts. The engine caught after a couple of turns and held revs without any problems, even with 3-week old petrol.

Headlights: noticeably brighter, but it's the kind of thing that I'll get used to in about five minutes. No issues with high / low beam. One thing that I didn't expect was to have the instrument lights work better, as well... the speedo & tacho dials are now finally illuminated properly.

Carburettor adaptor epoxy: slight improvement in engine running and AFR consistency, not huge. I think it was necessary, but the major issue is to get some heat into the carburettors (in a controlled way) before fuel mixes with air, to get that petrol warmed up a bit.

[OddDuck]

A short post concerning something interesting I tried and tested today. It's cheap, it's easy, and it's well worth giving a go before spending serious dosh, if you're having issues with your bike.

Clean the connectors to your CDI's.

I'd been having trouble cold starting, issues with mixture strength as reported by the AFR gauge, and odd surges in power while running. It had been getting worse (very slowly), but yesterday the bike wouldn't start. I had the carburettor heaters on and warm carbies, turned the motor over until the battery started having problems, no joy whatever. Frustrating.

Slept on it, did some reading, had a think about what was cheapest and easiest to try first, and got the connectors to the CDI's unplugged and had a look at the push-fit terminals used. Ducati have used what look like the highest quality 3.2mm push fit spade lugs I've ever seen, they don't push on hard but they don't need to. There's a very nicely formed spring plate to ensure electrical contact.

The issue is the low voltage used to power the CDI's. 12 V isn't much and it doesn't take much dirt / oil / silicone gasket grease etc to interrupt it... guess what I waterproofed the CDI's cracked silicone potting with. Of course the silicone gasket grease has been migrating and it's got into the connectors, taking dirt with it and compromising the spade lugs contacts.

A quick spritz with CRC 2.26, make-and-break the connectors three times each, and try the bike like this with a freshly charged battery. Huge difference. The bike started easy (with carb heaters) and ran better than it has run in quite some time. Testing over the hill in the Wairarapa at roughly 10 C confirmed it.

I can't say it'll fix everything but for the cost of a can of CRC 2.26, it's well worth a try.

[pete376403]

Standard diagnostic procedure (for me anyway) with computers and the like is to reseat connectors before replacing parts, with printers especially due to the constant vibration (eve worse in old style impact printers) resulting in fretting corrosion. Motorcycles could be considered a fairly harsh environment for connectors. Explained better here: https://www.researchgate.net/publication/208884472_Overview_of_Fretting_Corrosion_in_Electr ical_Connectors

[OddDuck]

Might have had a bit of a result tonight... for several years I'd been considering the possibility that the CDI's aren't 100% any more. The bike's still running the original Kokusans and it's been twenty years. How to test a CDI (via the magic of Google) seemed to be limited to bike goes / bike doesn't go / witchcraft. The forums weren't very helpful.

So I did some reading and found that most CDI's work by charging a capacitor up and then firing a high voltage pulse through the coil's primary winding. The pulse is of the order of 250 to 600 V. The coil's secondary winding then steps the voltage up to the level where it can make a spark. The pulse isn't a nice, regular sinusoid or anything easy to measure with a standard handheld multimeter, but an oscilloscope might do it. There are a few of these floating around on Trademe; at $100-ish secondhand for old and thrashed they're a lot cheaper than buying a brand new CDI, which is the usual test.

A word of caution: make sure you don't blow the inputs. The one I borrowed from work was rated to 400V on input. I put the probes to 10X anyway, thus making input limits 4000 V, and set to with it like that.

Test procedure turned out to be simple: get a connection in to the lead connecting CDI and coil (stuff a wire in), clip into this and use the battery negative for a ground, then get bike started and check the trace once the engine was idling. I had to do some work with the settings to get a stable, measurable trace, but once set up it was quite repeatable. Results are pictured below. I got the same trace on vertical and horizontal cylinders, so there was no significant difference between CDI units. They're both putting out roughly 400V to the coil over a pulse duration of 8 micro-seconds, with lots of post-fire bouncing going on. Presumably that's inductance in the coil shooting back at the CDI... or something electrical like that. One of the neighbor's kids started making a fuss so I didn't rev the engine to see what happens at high RPM. Maybe on Saturday afternoon or something.

Anyway, the result is that I don't have to spend $$$ replacing CDI's, unless I want to go fancy and upgrade or something. The originals are still working just fine.

[Voltaire]

I suspected the ignition on my 900SL but issue was those kehin flatslides and lack of choke.

With rejetted stock carbs back runs nice ( does however need new float valves, which two months later I haven't bothered to do)

Currently funds diverted to the more usable R90s

I was going to bin the ignition and fit one of these

http://www.fastbikegear.co.nz/index.php?main_page=index&cPath=706_787

[OddDuck]

I suspected the ignition on my 900SL but issue was those kehin flatslides and lack of choke.

With rejetted stock carbs back runs nice ( does however need new float valves, which two months later I haven't bothered to do)

Currently funds diverted to the more usable R90s

I was going to bin the ignition and fit one of these

http://www.fastbikegear.co.nz/index.php?main_page=index&cPath=706_787

Yeah, I'd got curious and did a spot of reading about them. They do sound pretty sweet - check this youtube of the Fastbikegear Frankencati wringing its nuts off:

https://www.youtube.com/watch?v=l6u5wi9Mvjo

Of course that's a very highly modded bike, I expect that the muffler has a lot to do with the sound.

The downsides so far seem to be:
- price
- sensitive to EMI emissions from the coils so relocation of CDI to tail might be needed and / or shielding on all electrical lines
- won't work well with CA Cycleworks coils
- can have problems with corrupted firmware (OK, once in a blue moon, but it's happened)
- doesn't like the battery getting a bit flat

Full credit to Liam, he's completely open about these issues and welcomes discussion of them.

In terms of reliability of the OEM Kokusans, they actually did let me down once, in the worst rain I've ever ridden in. Bakeout (at 50 C, fan bake oven) and silicone seal grease got them going again.

For now, I'll keep going with the Kokusans, since going to Ignitech is going to cost $$... need coils, Hall sensors, TPS as well as the programmable CDI.

[Voltaire]

Yeah, I'd got curious and did a spot of reading about them. They do sound pretty sweet - check this youtube of the Fastbikegear Frankencati wringing its nuts off:

https://www.youtube.com/watch?v=l6u5wi9Mvjo

Of course that's a very highly modded bike, I expect that the muffler has a lot to do with the sound.

The downsides so far seem to be:
- price
- sensitive to EMI emissions from the coils so relocation of CDI to tail might be needed and / or shielding on all electrical lines
- won't work well with CA Cycleworks coils
- can have problems with corrupted firmware (OK, once in a blue moon, but it's happened)
- doesn't like the battery getting a bit flat

Full credit to Liam, he's completely open about these issues and welcomes discussion of them.

In terms of reliability of the OEM Kokusans, they actually did let me down once, in the worst rain I've ever ridden in. Bakeout (at 50 C, fan bake oven) and silicone seal grease got them going again.

For now, I'll keep going with the Kokusans, since going to Ignitech is going to cost $$... need coils, Hall sensors, TPS as well as the programmable CDI.

Yes it does seem to add up.
I've run one on my track R100 BMW for a few years total loss with a non hall sensor with no issues. Must be a Ducati thang...

[OddDuck]

I suspected the ignition on my 900SL but issue was those kehin flatslides and lack of choke.

With rejetted stock carbs back runs nice ( does however need new float valves, which two months later I haven't bothered to do)

Currently funds diverted to the more usable R90s

I was going to bin the ignition and fit one of these

http://www.fastbikegear.co.nz/index.php?main_page=index&cPath=706_787

Could raise a few bob for the Igni gear by selling the old CDI's on TM, especially if they're still going just fine... cost at the dealer's for these dinky little black boxes is crazy numbers. Even ex Stein Dinse they're $250 or so each landed.

[OddDuck]

Getting back into it after the recent midwinter ride to Castlepoint and back... the engine started running rough on the return into Masterton. It kept running rough the whole way home. A quick check on the plugs showed both with carbon deposits, the vertical plug worse than the horizontal. I swapped the plugs out and the issue disappeared.

Carbon fouling would happen if:
Weak ignition system and therefore weak spark;
Plugs were a grade too hot and therefore never got hot enough to self-clean;
Liquid fuel was being drawn into the engine and burning onto everything.

It's been a few years, I've tried a few things, and I'm inclined to think that the bike has a design issue with the placement of the carburettors and the length of the inlet manifolds. Thinking is one thing, though. Knowing is another. So I had a think about how to measure what's going on, got the thermal imager out again, and this time I marked surfaces with bits of masking tape so that the imager had a decent target.

A quick note about thermal imagers or radiation thermometers: they don't like shiny metal as a target. Oxidised is fine, so is painted, but any bare metal is basically a mirror to a long-wavelength IR device even if it's dull grey in the visible. A single layer of masking tape applied though and that's it, problem sorted. The tape is thin enough to match the temperature underneath it, but IR-absorbent / emittent enough to make a clean target.

So I got the tape out in a few places on the carburettor flank and along the lengths of both inlet manifolds. I warmed the bike up at idle and then started playing with the throttle while checking temperatures. The images nicely show a gradient along the left-side inlet manifold, about the clearest data from this night's work. It was getting late by this stage so I halted proper testing, but I did find something worth checking further: the inlet manifold temperature will drop with the throttle being opened, but recover with the throttle closing. It makes sense. More throttle means more air, more fuel, and thus more evaporation, pulling heat from whatever surroundings it can. The only heat source for the inlet manifolds is conduction from the cylinder heads. What was instructive was seeing the indicated temperature ticking down on the imager. It went from about 35 C with idle throttle (at the boot insulator end) to approximately 13 C with 1/8th throttle and revs at around 4000. This took a few seconds to happen after the throttle opened. Ambient was around 12 C.

These numbers are anything but solid. The engine wasn't properly warmed up, I didn't properly check throttle position or RPM, air temperature was guessed at being equal to the imager reading off the garage floor, and any change in ambient air temperature would affect these results anyway.

What does matter is the pattern of the behaviour. The drop in inlet manifold temperatures corresponds with a behaviour I'm monitoring on the AFR gauge during sustained runs at 100 kph. Initially the mixture is perfect, then the ratio increases, indicating lean conditions. It takes a few seconds to start moving and then stabilises to a value which seems to be set by ambient temperature. I think that what's happening is fuel dropping out of vapour – or never vaporising in the first place – immediately in the throats of the carburettors and over the walls of the inlet manifolds. There simply isn't enough heat getting into these to ensure proper running of the engine.

[OddDuck]

And now for the fix... a while ago Kickaha had suggested shifting the oil cooler upwards, putting the carburettor bowls into its slipstream. I'll leave that possibility open, but for now I'll try something harder, namely applying controlled heat to the carburettors and the inlet manifolds.

It has to be controlled heat. It has to cope with changes in:

ambient air temperature
fuel temperature, as delivered from the tank
engine temperature
throttle position
slipstream velocity

The thermal load will vary enormously. I'm not yet sure if setpoints can be fixed, or need to be tweaked to match changes in ambient – I need the carburettors hot enough to vaporise the fuel properly and without icing, plus the inlet manifolds hot enough to prevent vapour condensing out. The two setpoints will be different. It's already clear that the manifolds will have to run hotter than the carburettors.

Adding to the fun and games... the system can't load the electrical system of the bike too much, there aren't too many more watts spare after the AFR gauge. Whatever I build has to work despite dirt, vibration, oil, heat, condensation or rain, gravel, tar, and bugs. It would ideally be simple enough to fix or patch up while on tour, and if it fails, it shouldn't take the rest of the bike down with it. The setpoints should be precise and adjustable, too – chances are that I'll need to spend a while tuning these. I'll also need the temperature indicators visible so that I can see what's happening while I'm riding.

So, how to do this. I spent quite some time thinking about the problem and trawling the web. The short answer there is that nobody appears to have done what I want to do, or at least nobody's bothered going public with it. There are passive, semi-controlled solutions:

heating the inlet manifolds by engine coolant
heating the inlet manifolds by heat stove over exhaust manifold and using a heat riser
using electrical heaters in the carburettor bowls
directly running exhaust over the inlet manifolds
running fuel lines past exhaust manifolds

The heat stove option offers thermal control by either wax pellet motor or bimetallic spring. These turn a butterfly valve on the heat riser, the whole thing transfers energy by rising hot air, and that's about as sophisticated as any control gets. Most of these solutions are from the car world and are designed to work under a bonnet.

Cutting a (very) long story short, I've decided to use heat stoves on both exhaust header pipes, electrically controlled fans to draw air despite slipstream, and heat jackets placed over carburettors and inlet manifolds. The system will work via on/off hot air. Temperature control will be via the fans and some of the thermostat boards used earlier, with sensors placed on the carburettor bowls and the inlet manifolds.

I spent way too long trying to think out every feature before I realised that it isn't possible to design this in advance. This is going to be one of those jobs where it's learned as I go. I'll have to build, test, modify, or possibly build again. I went out and bought some stainless steel dairy tube and elbows, and have started hacking up some rough first-try heat stoves and jackets.

[OddDuck]

A couple of quick notes about the dairy-grade 304 welded seam tubing that I'm using for the heat stoves.

It's extensively cold-worked. When the tube is made, it's rolled up from sheet metal and then seam welded. The elbows are then swaged straight out of bits of that tubing. The process leaves the material bright, but rather hard from cold working... I took the points off a few drills before I realised what was happening and that the material needed to be annealed before being drilled.

The LPG torch did work, but wasn't quite hot enough used as pictured - next time I'd like a hearth of firebricks to surround the work and keep some of the heat in. It'll help to raise the temperature a bit. What I'd found courtesy of the web was that annealing temperature for 304 is supposed to be 1010 to 1090 C, followed by rapid air cool to room temperature. There's no way this is getting to that peak temperature. By eye, I make it 900 to 950, which is the zone where stress embrittlement can become a problem. It did shift the material from not drillable to workable, though... The other thing was that there were a lot of problems with material springing closed on the blade while being hacksawed. I had to take the half-elbow cut in stages and work my way around, resorting to a Dremel for the inside curve.

Most commercial (automotive) heat stoves are stamped out of one piece of plate, after doing this work I can see why.

[Ocean1]

I took the points off a few drills before I realised what was happening and that the material needed to be annealed before being drilled.

Aye, some stainless is hideously poorly treated ex factory, literally unworkable. But those bends, (Ultibend?) aren't bad, it's far more likely you've work hardened it with the initial drill friction.

The trick is, firstly to use decent quality drills, 'cause most of the sets you buy at Mitre10 et al are shit. Secondly halve the rpm you'd use on mild steel, (and if in doubt halve that again) and double the pressure. Use a cutting agent like Rocol RTD.

But yes, there's a bunch of stress built into any cold worked stainless, and you have to be bloody careful cutting stainless tubing with a grinder in particular.

[pete376403]

Wouldn't it be easier (and probably cheaper) to build the prototypes using plain old exhaust tube ('muffler moly") and then go for the nice stainless once the design has been worked out? (or what I would probably do, design the prototype in exhaust tubing, shoot it with some flat black rattle can and call it done)

[OddDuck]

Aye, some stainless is hideously poorly treated ex factory, literally unworkable. But those bends, (Ultibend?) aren't bad, it's far more likely you've work hardened it with the initial drill friction.

The trick is, firstly to use decent quality drills, 'cause most of the sets you buy at Mitre10 et al are shit. Secondly halve the rpm you'd use on mild steel, (and if in doubt halve that again) and double the pressure. Use a cutting agent like Rocol RTD.

But yes, there's a bunch of stress built into any cold worked stainless, and you have to be bloody careful cutting stainless tubing with a grinder in particular.

Yep, gotta go shopping. Sutton / P&N / Evacut ? I'd been using Bosch drills (yes, off M10) since they'll sell single sizes OTC on a Sunday, but you're right, it's time to order in a decent set of drills.

Slowing down and pressuring up is going to require purchasing a drill press. I'd been putting it off for a bit but thinking about it now, a pedestal drill press would actually go in to the garage and avoid taking up space on the bench.

Cutting tubing with a grinder: agree, death on wheels, literally. The tubes that I was cutting were springing open (no problem) or pinching shut (big problem), it's why I was using a hacksaw rather than powertools. I can see a lot of exploding cut off wheels from that sort of thing.

[OddDuck]

Wouldn't it be easier (and probably cheaper) to build the prototypes using plain old exhaust tube ('muffler moly") and then go for the nice stainless once the design has been worked out? (or what I would probably do, design the prototype in exhaust tubing, shoot it with some flat black rattle can and call it done)

Weelll... at the moment the only source I've found for stainless muffler pipe is Redline Performance and they wanted $99 plus delivery for a 1 meter length of 2.5" diameter. It was $99 for a single elbow too. It was much cheaper to go to Steel and Tube and buy 304 ss OTC for full cash. That said if you know where I can get 2" / 2.5" stainless tube / bends etc for reasonable coin then I am all ears :niceone:

I hear ya on calling the prototype the finished item!!

[OddDuck]

A wee bit more work tonight - I'd wanted to be able to mount / dismount the heat stoves without any need to take the bike's exhaust system apart. The plan was to split the heatstove down the centerline, use stainless steel hose clamps to assemble as well as hold heat wrap tape on, but the halves need to be spaced and centered on the exhaust pipe. I've decided to use cap screw heads as the spacers / locators. M4 cap heads had about the right height for the job.

So tonight's effort has been to cut some M4 cap screws down a bit, put them into place, and rivet them in by crushing the threads in the vice. I'll probably weld them in properly later, for now they look a bit medieval.

[Ocean1]

Yep, gotta go shopping. Sutton / P&N / Evacut ? I'd been using Bosch drills (yes, off M10) since they'll sell single sizes OTC on a Sunday, but you're right, it's time to order in a decent set of drills.

Slowing down and pressuring up is going to require purchasing a drill press. I'd been putting it off for a bit but thinking about it now, a pedestal drill press would actually go in to the garage and avoid taking up space on the bench.

Cutting tubing with a grinder: agree, death on wheels, literally. The tubes that I was cutting were springing open (no problem) or pinching shut (big problem), it's why I was using a hacksaw rather than powertools. I can see a lot of exploding cut off wheels from that sort of thing.

Yes, I keep an eye out for sales on any of those brands.

There's times you can't use a drill press. A good speed control helps, so does a short series drill, (or a rivet drill, double-ended). And getting the cutting edge shape right, in this case just minimum trailing edge clearance.

I cut stainless tube with a 5" grinder regularly, you just need to be aware of the potential issues. The big divots up my RH wrist are from putting the grinder down too quickly and not paying attention, broke the disk on the edge of the vice.

If you keep an eye on tardme you often see those early cheap drill-mills that people bought years ago thinking they're some sort of mill, have since repeatedly discovered otherwise and have sat in the corner ever since. They often go for what you might pay for a half decent drill press and have some additional usefulness.

[OddDuck]

A spot of progress in bits and pieces over the last few days... no pictures this time sorry.

1) Carburettor jacket.

I spent some time tonight playing with bits of gridded paper and cardboard, trying to mock up a jacket that'd fit around the carburettors in situ while they're in the frame. Not much joy... lots of clutter in the way. Frame, hoses, wiring etc... it just isn't possible to simply drop a jacket in, as my original idea went. There's also no easy or obvious way to mount the thing to the frame.

The other option is to mount the jacket to the carburettors themselves while they're out of the bike, then drop the whole lot into position as a single unit. The issue with that idea had been mounting points. Tonight I finally realised that the carburettors are paired. There are three posts between the two bodies, with three cap screws on each side securing them together. It's possible to replace the cap screws with male-female threaded spacers. This will secure the two bodies as before, while providing threaded sockets for mounting side plates to the carbies. These side plates can then be the basis for mounting the jacket.

Because the jacket will be fitted to the carburettors directly, it can be mounted close and even be a wraparound design, I can duct warm air right around the carburettors instead of leaving the backs open. I think this is the way to go here.

2) Inlet manifold heater fan.

This will have to be run by a 12V dc motor and able to handle air at 100-ish degrees C continuously, possibly up to 200+ intermittently (especially likely on fan start during on-off operation while tootling around town). The inlet manifolds are really going to need this sort of heat, particularly under sustained running.

There aren't (as far as I can tell) any commercially available fans which can handle this requirement. Doesn't have to shift much air, doesn't have to generate much static pressure, just has to be able to cope with a lot of heat. Small, light, compact (don't have much room to fit it), doesn't draw much current either... these requirements don't make it easier.

Currently my best idea is to find an old turbocharger, strip it down to impellor housing and impellor, maybe keep the bearings and shaft, and fit a motor independently. I'll use a heat spacer of some kind if I have to. This idea has taken around a month or more of thinking... I just can't see anything else which has a chance, except maybe using a fan blowing cold air through a venturi and thus drawing superhot air through piping, without the fan itself ever being exposed. The venturi would not be an efficient way to shift air, though.

3) Hot air line filters.

I just realised that I really do need filters of some kind (probably wire mesh) in the hot air lines. I've got to protect those fans against bits of leaves, road grit etc. The heat stoves are both completely open to outside air, it's not a closed system by any means. This shouldn't be a big deal, some kind of inline canister should do the job.

4) Hot air line hoses.

Currently I'm thinking that I'll give radiator hosing a try, for both air lines, mixed with lengths of metal tubing where needed. There are very nice looking bits of braided hosing around, but that's for later. It's easy enough to fit.

5) Carburettor jacket fans.

I've ordered a pair of metal-bodied, long life at elevated temperature, computer fans. They're rated at 100,000 hours at 60 C, which should be more than enough for the job. Weather sealing may be an issue but we'll see if that can be sorted out by jacket design.

6) Heat stove slipstream insulation.

There isn't much point in a heatstove if it loses most of its heat to slipstream. Accordingly I've ordered some of the dreaded header tape. There'll have to be a lot of practical experimentation here in order to find what length of heat stove provides required heat while on the motorway, versus not cooking the exhaust header while rolling slow in traffic with both warming systems not drawing air.

7) Recirculating hot air in order to boost the temperature.

It can be a loop system if needed. It's unlikely that I can get much heat off the exhaust headers in one pass only, but this is one for practical experimentation first.

Anyway, slow progress, lots of metalwork to do over the next few weeks.

[Voltaire]

Is all this work from the original crack in the frame, leading to modified air box and flat slide carbs?

[OddDuck]

Is all this work from the original crack in the frame, leading to modified air box and flat slide carbs?

Yeah, I never really stopped... there was always the next thing. I treat it as a chance to learn. Anyway, 'tis the season to wrench.

[OddDuck]

A little bit of progress on a couple of fronts today... inlet manifold covers and the carburettor jacket.

One of the issues with designing these components has been the difficulty of taking measurements. Things are at weird angles, there's no clear datum to work off, that kind of thing. The idea I had today was to use the aluminium plate and a set square. I'd place the item onto the plate, arrange it so it was silhouetted against the paper, then use the set square to help trace the outline. The square means that if things are 100mm or so up off the paper, it's still possible to get the outline right to within a millimeter or two.

It's a bit laborious but it works. The major issue is holding the item (whatever it is) at the right plane, and fixed so that it doesn't move if I bump something with the square. The intercooler pipe is stuffed onto the inlet manifold insulator rubber boot for this reason - by a happy accident it fits on snugly and makes a perfect brace for the tracing.

The aluminium tube is an 2.5" intercooler connector pipe with a 45 degree bend. I've used a large socket, wrapped in duct tape to match diameters, as a brace against crushing in the vise while it's being hacksawed. This will be the cover for the inlet manifold, now I need to make internal ribs to hold it in place.

[OddDuck]

Some brief work tonight convinced me that outlines traced onto paper aren't going to sort out the carburettor jacket. The carburettors are too complex to model this way easily.

The rather boxy preliminary concept was modelled in card as just the front plate, and was promptly failed when I tried connecting a pod filter. It's just too far forward on the inlet trumpets and will get in the way, no matter how it's set up. I'll have to go under the forward brace bar if I want to clear the pod filters mounting points properly.

The angled card has square holes - these roughly mark the position of the two air duct fans. I want to blow warm air onto each carburettor base and then use the jackets to direct the air over as much of the carburettor body as possible. There's got to be enough thermal conduction from the carburettor body into the throat to prevent icing.

The playing with card did give me an idea, though... trial and cut-to-fit direct on the item does have possibilities. I want close fitting jackets, if possible. 5mm spacers and scissored card could be the way forward here. It may also be possible to mount panels via rubber box feet and external clamp or screws, but I'll have to see how I go.

[OddDuck]

Next try, change of method again, some progress with spacers and card. The spacers are paddle pop sticks, cut to length with a pair of engineer's pliers and stacked together with masking tape. Nice and easy to work with. These then set working planes and clearances from the carburettor body. I stuck a panel onto the side with double-sided tape and used that as a start plane. From there it's just a question of building up, trimming edges, and then getting panel shapes and sizes for the finished jacket.

I've decided to try for two close-tolerance jackets instead of one larger wrap-around. A single jacket would leave a big gap between the two bodies and most of the ducted hot air would be blown straight through that, unless I use baffles. They'll be pretty boxy when they're done but first steps and all that... just as long as it improves the bike's behaviour on cold days.

It occurred to me that this isn't the only way to design a jacket for a complicated object. 3D scanning and printing / casting offers options, so does clay and fibreglass, but both of these are out of my reach at the moment. This is the lowest resource base way to do it, it's just scissors, card, pop sticks, tape, pencil and ruler to design, then basic sheet metalwork for the actual build. I might need a lathe for the mechanical mounts, and it'd be nice to zip seams together with a TIG, but that's as involved as this gets.

[pete376403]

I would have thought glassfibre would be easier - wrap the carbs in gladwrap, build the shape directly onto them using clay / plasticene, and then lay the 'glass straight over that. Make two halves with a flange that can be screwed or clipped together

Glass matting and resin is reasonably priced at Mitre10.

[OddDuck]

I would have thought glassfibre would be easier - wrap the carbs in gladwrap, build the shape directly onto them using clay / plasticene, and then lay the 'glass straight over that. Make two halves with a flange that can be screwed or clipped together

Glass matting and resin is reasonably priced at Mitre10.

Ta for that - still trying to work through ideas. I've spent way too much time and energy over the last couple of weeks trying to sort out the details.

I had some time today to get back into the heat stove and weld the pieces up, the split into three sections was necessary because a normal 90 degree bend didn't quite fit. Not much to say here except that ensuring it'd fit on the vertical cylinder exhaust pipe meant doing the welding with it clamped to said exhaust pipe. The crocodile clips proved helpful while doing the tack welds.

[AllanB]

Try Autobend for stainless bends etc.

My lads old 1986 Ford Laser has a summer/winter preheat lever on the air cleaner inlet you flick over when colder. Which moves a flap to divert the incoming air off a tub over the exhaust manifold - same concept you are running. Works too - I had a 1980 SE Corolla years back with the same set up.

[OddDuck]

Thanks Allan - had a look at Autobend and they look pretty good...

Might have just found out a couple of useful bits of info:

1) If you've got a sharp-edged barb on the fuel tap, there's a chance that it'll put rubber shavings into the fuel system if you have to put the hoses on and off a few times. These shavings can jam needle valves in carburettor floats, leading to fuel pouring into the inlet manifolds, etc etc... it was pure luck that I saw it before I put the pod filters back on.

2) If you're smart-charging the battery over winter and it won't, for no obvious reason - before replacing the charger or the battery - disconnect everything off the battery and try charging directly with crocodile clips to the terminals. I've got quite a few add-ons running on the bike now and have been finding that both the Oxford Oximiser 9900 and the SCA general purpose smart charger wouldn't drive properly. My best guess as to what's happening is that the charger thinks that the battery is damaged, so follows its design and refuses to charge.

For now I've put the bike back together as it had been for last summer, with the carb bowl heaters in place for cold starting. It's become clear that it'll take weeks or months to make the bits needed for winterisation, in the meantime it'd be good to have the bike for a sunny day.

[Voltaire]

I finally got around to fixing the leak on the stock Mikunis today. I thought it was just a matter of taking the fairings off.....
had to remove the battery/coils/ign and airbox. Fortunately having done this twice it does not take long but.
Once the airbox was off took off the float bowls, replaced the float needles,float unit and bowl seals. also made up a drain so if it happens again does not drip on to hot bits.
Full choke and it fired right up, choke off after about a minute and idled nicely.
WOF next week and get out an ride the thing.
For the rest of the weekend I shagged about with my F*&K'n Norton and its dragging clutch so as I can get it woffed and on the market.:innocent:

If they made a choke unit for the flat slide carbs they would work fine imho as once they warm up from engine to manifold conduction they are fine.

[OddDuck]

I finally got around to fixing the leak on the stock Mikunis today. I thought it was just a matter of taking the fairings off.....
had to remove the battery/coils/ign and airbox. Fortunately having done this twice it does not take long but.
Once the airbox was off took off the float bowls, replaced the float needles,float unit and bowl seals. also made up a drain so if it happens again does not drip on to hot bits.
Full choke and it fired right up, choke off after about a minute and idled nicely.
WOF next week and get out an ride the thing.
For the rest of the weekend I shagged about with my F*&K'n Norton and its dragging clutch so as I can get it woffed and on the market.:innocent:

If they made a choke unit for the flat slide carbs they would work fine imho as once they warm up from engine to manifold conduction they are fine.

Yeah, been there many times with the stock Mikunis and now the FCRs in terms of getting them off the bike to be worked on. Surprising how much work is involved in removing carburettors with an L-twin. A transverse (Moto Guzzi) or flat (BMW) twin would be much easier, since the carburettors are out in the breeze and can be got at directly. Ditching the airbox, fabricating a battery box, and going to pods made maintenance quite a bit easier.

I've started riding the bike again this week in preparation for summer, making sure any issues are sorted early. The electric heater system I trialled as an alternative to a choke is working - the bike starts first go and idles smoothly - but with one issue, it takes about three minutes for the system to heat to temperature. A choke butterfly is set to go in seconds.

I'd seen pictures of a cold starting enrichment system on some Keihin carburettors. It seems to be an auxiliary fuel jet which is opened by a cable and needle valve, fittable as an accessory to single carburettors. It doesn't look like it's fittable on banked carburettors. It's truly bizarre that a carburettor as well thought out as the FCR series doesn't have provision for cold starting, but there we go... maybe that's a dedicated racetrack thing?

Anyway, that brings me to a question that's been on my mind for a while now. I have a solution to the FCR cold starting issue. There are a few of these carburettors around globally. Are other people likely to be interested in this commercially, i.e. is it worthwhile bringing a product to market?

For the record, I don't rate the odds of this happening, this is not a trivial undertaking. To go to market I have to design and make the thing to a much higher standard than has been built for prototyping. There'll have to be a company registration, I'll have to sort out deals with various online resellers, or start my own website and ordering service. Then there's tax, record keeping, trying to get this idea from it being just me working my arse off after hours from the day job to being something that other people do for me, etc etc... and under it all, the truth that this is an ultra-niche product with a tiny market, most of whom use the 3-squirts and crank the motor until it goes start method anyway.

Anyway, thoughts from fellow KBers and experiences would be appreciated.

[Voltaire]

The search for Ducati Perfection continues....

The stock carbs are 38mm which is a good compromise between WOT performance and mid range response.

Similar to old BMW Bing carbs in as much as you open a butterfly valve and the vacuum lifts the slide.

Dellortos work well on BMW's but need a bit of choke or the few squirts of pump jet.

Everytime I did that on the Sl I thought about the poor sprag clutch and starter motor.

Facebook sent me a photo from last year and it was the SL with a pic of the speedo.....I had done about 60kms on it in a year :weep:

Going to take it for a WOF this week and its been full choke and immediate start.

Conclusion... running and not perfect is better than sitting in the shed :lol:

A google search tend to suggest its been a problem for some years, yet others claim its not... mystery.

[OddDuck]

Voltaire - Maybe the Sl-on-FCRs starting issues were some combination of bad idle tuning on the carbs and possibly a slightly weak ignition? I'd found that the slow fuel jet and slow air jet both wanted a tweak from as-supplied in order to start working properly.

As to progress... design work on the carb jacket has stopped for now. Work work has gone nuts over the last couple of weeks, hopefully it'll ease up again soon.

I did manage to get out for a tootle on Saturday. The bike started behaving badly, i.e. lots and lots of vibration. It was bad enough that I cancelled the ride, came back and took the exhaust system off again in case I'd left a rag stuffed inside. Nothing there, exhaust's fine, so I went looking.

Exhaust pulses aren't smooth, at idle or at revs (tested by putting hand into outgoing gas stream). Lots of intermittent firing going on. Right... the spark plugs were showing clearly different combustion behaviour. One was super clean, the other borderline fouled.

I finally (should have done this years ago) swapped the CDI units over and went for a ride. The vibration didn't get much better (it did, slightly), and on return, the fouled plug had started to clean up. The pristine one might have had the very beginnings of carbon buildup, but it was minor.

That's the basic test for a sick CDI. However... in the interests of being sure (and keeping this post brief, and readable)

Testing I did earlier:

Compression: same on both cylinders, each OK
Fuelling: identical settings on each carburettor
Intake: no issues with either pod filter
Pickup coils: gaps reset last summer, resistances OK, magnets seem fine
Ignition coils: resistances tested OK, coils are new enough that there shouldn't be issues

Testing I've done in the last few days:

Pickup coils: resistances OK
Ignition coils: voltage to each OK, between 11 to 13 V with engine running
Carb synchronisation: off, readjusted to correct, no change in vibration

and of course swapping the CDI's affected the condition of the plugs.

It's really the last one that has clinched it for me. The bike's been fouling plugs on the vertical cylinder since I've bought it. It's been 22 years, it's not beyond belief that at least one of the CDI's is on the way out.

It's possible to replace with OEM Ducati via Stein Dinse at reasonable money - approx $225 landed per each - I'll keep that as a reserve option, but for now I'm keen to give the Ignitech gear a try.

[Voltaire]

I suspected the ignition as my mate bought a 600ss semi runner and turned out to be one of the ignition units. I gather they are not highly thought of and now 20+ years old.
Looked at Liams plug and play Ignitech but he said probably good to fit Nology coils too.....scope creep and about $600.00+
I did try with the FCR's did all the research, set up and jet checks. Once it was started and warmed up was fine for the rest of the day but what a pita starting it.
I'm happy with how it is now running stock bits.

My 900ssie was a good starter and runner....have you thought about fitting fuel injection?
As I mentioned I've got an Ignitech in the BMW, they are a nice bit of kit and liam is very helpful.

[OddDuck]

Ignitech ordered... I went the whole hog and bought the Nology coils, the HT leads to go with them, the hall effect pulley mount sensor kit and the TPS plus bracket for the FCR carburettors. Spendy, but I want more vroom. Or at least a bike that goes nicely for summer.

Liam did tell me that the CA Cycleworks coils will work with the Ignitechs, just not as well as the Nology coils will.

Fuel injection, well... I'd looked at it a while ago. I have to admit that FI would solve a lot of problems. There wouldn't be any issues with fuel condensation inside manifolds, for one. The issue would be that I'd lose the long inlet manifolds. I reckon they're much of the bike's character - lots of punch midrange, gobs of torque with it, beautiful soundtrack... it just wouldn't be the same.

Apparently similar happens if the bike is changed to split singles with short inlets, you get benefits higher up in the rev range, but lose the middle of the RPM range. Although I'd want comment from someone who's actually done it to be sure of that opinion, I'd thought pods would be bad but they turned out to be one of the best things ever!

I had another start on the carburettor jacket tonight. The latest plan is to use the three bars holding the carburettor bodies together as mounting points. I'll fabricate a bracket that fits to these bars and then attach panels to that.

[OddDuck]

Carrying on, after a breather (yeah, I got tired...) this time with the original Kokusan CDI units, because I was curious and why not. The workshop that I normally use is, ahem, in a state of renewal, and involved prototyping is going to have to take a back seat for a while. So, CDI's it is for now.

What's inside? And what went wrong? And can it be fixed?

Well, the first thing is to get in there. It's potted, thankfully not with epoxy. This one's sealed with a black silicone rubber. That's got to go before any sort of assessment or repair could be done.

There are commercial de-potting compounds. Presumably these need some sort of heated bath and proper chemical disposal afterwards. I don't have any of this, hence the tweezers and doing it the cheap, impromptu, and laborious way. I got most of the way down before realising that I had to take a hacksaw to the case and peel that off, since it was blocking access to the sides and base of the unit.

The photos below are nearly 8 hours painstaking work. One mistake and you'll break something off the board, too - I did that, bottom right corner. I think it's a resistor but can't be sure.

Anyway... de-potting silicone. Basically nothing that you can buy at the local hardware shop will dissolve this stuff. A witches brew of 2 parts isopropyl alcohol and 1 part white spirits will slightly swell and soften it, though. Toothbrush scrubbing with this solvent mix removes the really fine bits of torn silicone. This helped (particularly in the final stages) but it's no substitute for bulk removal by getting in with the tweezers, push-cutting to get a jaw below the surface, and then yanking the silicone out in little chunks. It's the only way the stuff seems to come off. After a while, components started to unearth. A jeweller's flat bladed screwdriver was useful to push or chisel the last bits of silicone off. It was a bit like archaeology.

As to the CDI itself, it seems to be a simple design featuring low voltages and the cheapest possible construction. It's made with a single layer PCB, surface mount components (mostly) and what looks like three carbon film resistors selected for trimming. There are technician's permanent marker notes on the heatsink - just some numbers, really. I presume that the square copper pads on the PCB are test points for use during manufacture and tuning.

The underside has a thyristor (I think; three-pin TO220 package, no visible markings seen so far) attached to a heatsink plate, with three electrolytic capacitors beside it. If I was going for a repair, it's a pretty good bet that this is where to start.

The heatsink mounted chip is directly connected to the ignition coil's primary winding, via the three-pin connector. It's clear that this chip carries a high loading, hence the heatsink. As to the electrolytics, well. They're cheap. They work. They're good for a while, but they're not stable forever.

Electrolytic capacitors are basically guaranteed to fail. The capacitor is formed by two aluminium foil plates wound into a spiral, with an electrolyte paste squelched between them, and the plate surfaces insulated with carefully-generated aluminium oxide. This is then cased and sealed. The electrolyte can dry out, or the oxide can be dissolved off the plates if the capacitor isn't charged by use. They're also anything but accurate. Brand new capacitors can have tolerances of +/- 20%, straight out of the box.

So, some very quick comments, based on what I see here:

1) it's not possible to test the CDI with a multimeter. Any test path has to go through too many different components, since they're connected in a circuit. Testing can be done once it's been de-potted, though.

2) components that are likely to fail can be replaced. That doesn't mean it's repairable. It looks like re-tuning is needed in order for it to run properly, at this stage I have no idea what this tuning would be.

3) the capacitors are rated to +85 C. This is a common rating for electrolytics, and electrical components in general. If attempting to bake moisture out of an old CDI, it's probably a good idea to keep temperatures at around 60-ish.

4) performance of this pattern of CDI will degrade with time. Components like film resistors and electrolytic capacitors aren't stable over the long term and values will shift by a few percent, possibly enough to affect ignition timing. YMMV of course. I have to confess that I've never tested the bike's timing with a strobe lamp.

This dinky little unit is worth more than $600 NZ if bought at the dealer's. What a pain.

[OddDuck]

Well, the bike's having trouble again... vibration while running, feels like detonation on at least one cylinder. Whatever's going on, I hadn't managed to track it down in previous work. I'm also (for now) stuck with the OEM ignition. I'm still waiting on the Ignitech gear.

So, back to testing the ignition - I put a few hours in last night to try to understand what's happening. I got stuck in with an oscilloscope and a strobe gun. I didn't find the problem but did notice a detail, plus got a bit further on how to test this stuff.

Detail: the OEM factory manual doesn't specify wiring colours for the pickup coil leads or polarity in the header. (Time to get the Haynes, I've wanted that manual enough times by now that there's no point in saving money on it any more.) When I connected my borrowed oscilloscope to the pickup connector, it showed clearly that there's a pulse up and a pulse down, or if you swap the pickup leads, it's a pulse down and then a pulse up.

This is important - a look at the stripped CDI confirms that there's at least a couple of transistors leading off the pickup coil connector and a connection on the right hand connector side to ground, through a couple of resistors and capacitors. The transistors will be firing on application of a pulse of correct polarity. The circuit may also be using the gap between the pulses to estimate RPM, although I can't yet be sure of this.

Testing: this has also shown a method of testing an inductive (or variable reluctance) pickup. Connect the oscilloscope to the pickup leads, turn the kill switch to Off, then cold-crank the motor. Inductive pickups don't need anything else running to generate a signal, turn the engine over and you'll get a signal off the pickup regardless. This is about the only way I can think of to check correct gapping / magnet strength / coil function etc without getting inside the engine cases.

Strobe: the gun I purchased is having trouble keeping up with increased RPM. I'm not sure why, yet. What it did show was that neither cylinder is running on the idle timing marks. The vertical is a few degrees early and the horizontal is so early that the timing marks can only be seen at the very base of the timing window.

So... it's a mess. I don't know what's going on or why. About all I can draw from the night's work, and going through the photos again this morning, is that I need to be a lot more methodical in this sort of work. Thrashing around at random isn't going to sort out what's happening.

[OddDuck]

A bit more work today - simply changing the oil, checking the filter screen, and pulling the alternator cover off to check the pickup coils for position and gap. This turned out to be a peace-of-mind exercise, there's been no change since I'd assembled them. The mesh screen and magnetic drain plug weren't peace of mind, though. There were metal flakes caught in the plastic screen and on the plug.

I also checked timing in case of having made an error on assembly. The timing is set by putting the engine to TDC on the second set of timing marks, as dictated by the viewing window, then the cover is removed and you lose the precision of the timing mark. If the engine is bumped, or relaxes, the only way to be sure is to refit the cover and reset the crank position as appropriate.

That said, the timing looks fine - maybe a degree or so of delay, but there shouldn't be a problem here. While I was in, I took a cheap plastic protractor and checked the accuracy of the timing marks. The photo makes it look like everything is off by two degrees or more, this is unfair since the protractor isn't properly centered. To get the photo I had to rest the base edge onto the pickup coils. Once centered - with the protractor lifted to clear the pickup coils, about 5mm off the flywheel surface - everything marked was correct to within a degree, as well as I could tell.

The remaining possibilities that I can think of are:

Bad valve clearances, leading to a hot valve
Lean mixture leading to detonation
Electrical interference on the pickup leads

Tomorrow's job.

[pete376403]

Looking for info on fuel injection for the bike, found this:
Note the comment about coold and hot starting :-)


Re: How many engines running on MS2/Extra

Postby Tassuperkart » Thu Oct 27, 2016 3:27 am
Hi All
Thought Id add my project.
Its a 1981 Ducati 900 SSD. Ive had this bike since new.

Image

MicroSquirt ECU/MS2-E. Currently configged as TPS for fuelling and MAP for ignition. It just likes it that way!
Single VRS looking at a custom 24/1 crankwheel
TTRIgnitions QuadraMap 2 channel MAP sensor. Phasing for cyl 1 coming from the QuadraMap.
Generic 40mm butterfly type throttle bodies with 250cc injectors
45L/Hr fuel pump
Continental ethanol (flex fuel) sensor
Nissan FPR (no vac sense) @38psi
Accel coils x 4 (twin plug heads) triggered by a Bosch 200 2 channel trigger igniter
Ford 2 wire idle valve
Generic "GM" CT and AT sensors
AEM WBo2
Comms via bluetooth adapter.

The bike has been extensively modified over its 35 year life with me and electronic fuel injection is the final piece of the puzzle.

Fuel injection is something I have wanted to do for decades but had never gotten around to it.
After quite a bit of dicking around, the stock dual VRS sensor were junked due to excessive noise and a VRS sensor from a Kawasaki KLR650 was fitted with a 24-1 wheel fashioned from an industrial chain sprocket to time the whole show.
The 40mm throttle bodies were sourced from a Chinese supplier and adapted to the engine using Ducati Monster rubber manifold stubs.
The engine starts easily and runs reliably from dead cold to stinking hot on a coarse startup tune and finer ECU mapping is well underway. The flex-fuel function works well and this twin plug, high compression engine loves the metho!!!

Im extremely happy with the outcome so far despite the very early days in tuning.

My only issues so far is some slight scratchiness at lower rpm, right off idle that is proving very difficult to map out and some occasional ECU resetting when running with the tablet online.

Cheers
Evan

http://www.msextra.com/forums/viewtopic.php?f=101&t=23167&p=487227&hilit=KLR650#p487227

[OddDuck]

Hmm... quite a bit of food for thought there! Yeah, it has been a bit of 'take a year and learn the hard way why ECUs, mapping and injection exists'

The next bike's going to be injected. I've finally come around to the idea.

In the meantime it's save up the bucks and try to keep this one running for summer... I really want to get out and ride. Currently am having a look at this thread:

http://www.ducati.ms/forums/57-supersport/59714-fuel-injection-flat-slide-carbs.html

[OddDuck]

Carrying on with the regular 3,000 mile service today, checking valve clearances, and the first time I've tried quick disconnects on the fuel hoses.

These make it possible to take the fuel tank off, instead of propping it up and trying to work underneath it. Wish I'd done this for the first service, what an improvement in access.

As to valve clearances, a lot seem to be badly out, closer shims in particular. Not sure why... I've also noticed something tonight which is a bit disturbing but worth mentioning to other high-mileage 2V Ducati owners:

If you've got a worn engine, your opener shim clearance is affected by whether or not you've rotated the engine immediately before trying the feeler gauge. This is with the valve mechanism fully assembled, with the opener rocker arm retainer clip in place.

It's quite noticeable: if I rotated a full cycle and measured immediately, I got a result about 0.002" further open to what I'd get if I waited about ten to fifteen seconds. This probably means that the rocker arm bores and mounting shafts are worn, not too surprising with 62,500 miles on the clock, but it does mean (to my mind) that it'd be easy to set the opener clearance to an apparent 0.004" but really have the engine running at 0.006" once things are spinning.

Should've checked these during the engine rebuild. Oops, spilt milk, a bit late now etc etc. If I rebuild the engine again I'll keep this in mind.

This means that I should go through the engine and re-check any clearances I've already set. Ignition behaviour is still waiting to be checked too.