Learning
Just left there, selling on hope? I guess it was running when it was dropped off, then non-bike people being left in charge of it possibly didn't put the battery onto a tender. I certainly didn't see one when I walked in.Originally Posted by BMWST?
Seller never got back to me about uplifting the bike from Turners and getting it running. Maybe he was reading my other thread.
Learning
First go using the CRC Weldcheck stuff.
Pretty simple stuff to use but it looks like it takes a bit of experience to get reliable results... I can't say that it worked particularly well for me. Some hassle, delays, and a shitload of really nasty fumes. In future I think I'll be doing a total immersion in the isopropyl / white spirits brew, scrubbing with a paintbrush and then going over the surfaces with a high-mag optic. Certainly it was a pain to clean up complex surfaces like gear teeth.
Anyway, here's the results. As far as I can tell, no cracks found in either component (despite my earlier comment about the bearing cup), any red lines are due to my pretty lacklustre rag wipe-down prior to development. The main drive gear looks fine after all. I want to re-check the bearing cup, though.
Forum whore
If he was he could see it couldnt go to a better home
Learning
Today's effort: getting the cases back together and then rebuilding the rest of the engine's bottom end. I've now got the clutch and alternator covers back on.
A very quick play with shims this morning sorted out the gearbox input shaft, now running with 0.085 mm free play. There weren't available shims to tighten up the clearances on the output shaft due to parts no longer available, although next time I'll check the situation with the same year 900 Monster, which uses the same engine. I'd sorted the parts issue in this way with the timing shaft gear lock washer.
Not really all that much to say here except that bagging and plain english labelling everything paid off. Prior experience really paid off. The engine stand and a second table to work off were very helpful.
Learning
Awww thanks mateIf he was he could see it couldnt go to a better home
FUN LOVIN CRIMINAL
The techs at work use a black light once they've done the treatment, any cracks literally glow
Learning
Today I realised that I've made a mistake and need to get the cases apart again. Dammit.
It's one of those situations where either it's a bit tough now or it's a lot tough later... going back in means losing around ten to twelve hours of work. Not getting this right means losing about sixty, plus waiting time for parts.
As to what went wrong... a couple of things, really. I misread the dial gauge. It wasn't 0.550 mm, it was 0.520 mm (see photos; I lifted the crankshaft with a screwdriver for the second one). The other one was that I did some back of an envelope arithmetic wrong. I divided 1.72mm by 2 and got 0.76 mm.
Oops. Big oops. It's 0.86 mm. There goes my 0.20mm preload, right there.
This happened because I was rushed, stressed, tired, pissed off, and didn't have a calculator to hand because it was the garage and who keeps a calculator in their garage. Going to have to change that.
A few other thoughts have occurred, while kicking myself. There are a few gotchas in this very important measurement.
Gasket.
New bearings, and what they're lubricated with.
Casing flex under contact.
The gasket is important for this measurement, for two reasons: it crushes between the cases, then it swells again once it gets oiled.
Some rough measurements from tonight, a brand new gasket which has never been used versus the old gasket rescued from the bin:
New gasket: 325 microns thickness
Old gasket, between cases, near screws: 315 microns
Old gasket, between cases, equidistant between screws: 365 microns
Old gasket, open space in sump with no compression: 385 microns
So it's pretty clear that oil makes the gasket swell up. Maybe the old gasket wasn't the same as the new gasket, but the trend is clear. One thing I can say is that the casing half bolts were damn tight, when I undid them earlier. The threads weren't clogged with ash.
Bearing lubricant: the stuff coating new bearings is thicker and stickier than engine oil. It has to be, it shouldn't evaporate off the bearing or allow damage during shipping. The issue here is that this stuff is part of the shimming measurement too. It'll get rinsed with engine oil once in use, so that lubricant boundary layer will change. Maybe the lubricant layer isn't more than a few microns difference, maybe it is significant after all. I do know that preload is quoted differently for re-used bearings than it is for brand new.
Casing flex: the measurement is directly affected by how hard the operator presses the crankshaft against the upper casing half during this measurement. The casing will act like a spring. There might not be more in it than, say, 5 microns, but the effect is there.
The one thing I can be reasonably sure of is the thermal expansion. The casings will run at around 120 C. That means I need at least 150 microns of preload, just to keep up with the differential expansion between casings and crankshaft.
Fun and games, fun and games. The casings have got to come apart again and I've got to re-run the free play measurement, now that the new gasket's had crush, oil and time. Maybe it's worthwhile washing the new bearings with clean engine oil too. The new target preload figure is 170 to 180 microns.
TWR - thanks for the info - at this stage I'll leave the crack testing, but it's good to know.
Forum whore
Do you really think the factory would take 20-30 microns into consideration when banging an engine together? Could they really take the time to select the parts (or have a range of parts with that variation for selective assemble) and still be able to sell the bike at a competitive price?
it's not a bad thing till you throw a KLR into the mix.
those cheap ass bitches can do anything with ductape.
(PostalDave on ADVrider)
Forum whore
maybe there is preliminary work done to optimize batches
Learning
(prior post edited because it was too long, too detailed and too speculative - the 20-30 micron thing is a reference to possible gasket crush during assembly and measurement, then swelling during service, thus decreasing bearing preload by 20 to 30 microns)
Hell, no. Not a chance. 50 to 80 microns would be about as good as you could hope for. This is Ducati after all. The engine designer / assembly procedure writer might take it into account though.
What I'm on about is that I think there's a couple of subtleties to what's going on. If you're being fussy (I am and make no apologies for it) then an effect with 20 to 30 microns is interesting, if there's a couple of effects like that and they add up then I reckon it's worthwhile understanding it properly. Put it this way, if I get this wrong then sooner rather than later I'll be stuck with a bike off the road again.
As to getting product out the door and making a buck... no way are they assembling cases, checking clearances, taking everything apart and fussing with shims, then reassembling and checking everything again, turning a heavy case assembly over on a bench. Nope. It'll be a coordinate measuring rig linked to a computer program that tells the assembly guy which shims to use. About five minutes on the machine and maybe ten assembly and that'll be it, done and out the door.
Learning
Stripping the engine down again is a weekend job - there's a lot of spreading out of parts etc, it's best done when there's six to eight hours available in a row. I've spent the week addressing the need to sort out the surfaces on the spigots sealing cylinder barrels to heads.
First thing: measure what's going on, on the cylinder head at least. I haven't looked at barrels yet.
I used a depth micrometer for this, finding (to my surprise) that there actually wasn't much variation. Going around clock marks on the spigot, everything was around 2.95-ish millimeters depth. Maybe plus 10 microns, maybe minus the same amount. The obviously damaged surfaces didn't measure as having been gouged any deeper. It's possible that the micrometer simply measured the remaining high spots, thus giving an optimistic reading.
Ok, so I tried fitting the cylinder barrel to the head. It didn't sit flat, it was possible to rock the thing back and forth, ever so slightly. Right. Should have been perfectly flat. Something's been banana'd, can't rebuild like this again.
The first thing I tried was Kickaha's suggestion of directly lapping barrels to heads. I got about ten minutes into this before I decided that it wasn't working well for me.
A few reasons...
Most of the lapping pastes around are meant to lap hardened steel alloy valves into whatever material valve seats are made from. They're not really meant for cutting aluminium. I'm sure someone somewhere does these aluminium pastes, it's just that I've never seen them. Anyway, the paste I had (cheap, generic engine work stuff - Powerbilt, billed as fine grade, 320 grit? - was simply too aggressive. I was getting nasty dig-in marks carved into head or barrel.
The cylinder head doesn't rotate freely around the barrel. There's a clash between the timing belt gate and where the exhaust header is mounted. There's only a very limited range of rotation - around 15 degrees or so - which just isn't enough to get the surfaces to properly match.
The spigots are different diameters. The barrel (external) is smaller than the head (internal) by about half a millimeter, which of course it has to be. These shouldn't jam together after being used. This means that surfaces could be lapped in one place, but fitted together in another, thus spoiling the matching between them. This joint has to be as close to perfect as possible, regardless of assembly variations. Flat going onto flat will do it, something that needs repeat positioning down to a few tens of microns won't.
I tried using an orbital motion instead a simple rotation, then various rotations at different centers, combinations of orbital and twist etc, then finally quit before I damaged anything too much. It's clear that a dedicated tool of some kind would give a better result, so that's the next step.
Learning
Next step: design and make the tool.
A trick I've used a lot over the years is to use wet'n'dry on flat blocks. It's not perfect but it's dependable, in terms of reasonably flat finishing of workpieces.
My idea was to lathe up a cylinder which would fit into a cylinder head. There'd be a sheet of wet'n'dry secured against its face and I'd simply press and turn the thing to cut the spigot flat and clean again.
I had a couple of mis-steps, making the tool... it turns out that decent slabs of aluminium plate can be hard to obtain at short notice. I tried buying a cheap cast iron barbell weight, with a view to machining that to size. Nope. I hadn't realised that cheap cast iron tends to case harden during the casting process. It is not easy stuff to work with once this happens.
In the end the tool was made from a harmonic balancer, a glorified belt pulley off the end of a V6 car engine crankshaft. There are a few similar scrapyard items it could have been machined down from. Anything with a big enough diameter and enough perimeter rigidity would do. I wanted a central core to press down on, though. Pressing on the outer rim would introduce distortions, so anything with a big hole in its center was out.
The other part of the tool was a cylinder guide. I want to fit the same tool to the cylinder barrels, have it remain centered, and turn and cut the cylinder spigots too. The black disc in the photo is a piece of turned ABS plastic for this purpose, it's meant to bolt to the tool and secure the wet'n'dry at the same time.
I used double-sided tape to carry the wet'n'dry for the cylinder head work. Final trimming of the paper to the tool diameter was done with knife edge running against the edge of the tool itself. I tried trimming with scissors and very quickly decided that I was just going to destroy these; the grit from the paper gets between the blades very easily.
The tool fits and turns in cylinder heads as it should, I ran the first cuts tonight. I haven't tried working on a barrel yet. Note the use of engine oil, buttered onto the paper prior to making any cuts - it's both a cutting fluid and also a keeper. I don't want loose bits of silicon carbide dropping through the cylinder once the engine is reassembled.
Learning
And results... the magnifying glass makes for a cheapo macro lens.
I'm happy with results from the first cylinder head, but 800 grit paper took a while. I went around the perimeter with the depth micrometer again and found that there's been less than 10 microns taken off in this cut, without any noticeable skew in the spigot face. At the same time the cut looks reasonably flat. Possibly it's domed slightly, but I don't have the gear to measure this properly.
Learning
... by getting another ride in the meantime.
Ducati ST2.
Went up today with a mate and did the deal, sorted insurance etc and then rode the new bike home. There are a couple of issues - I used these as bargaining leverage - and I'll cover these in a new thread. Nothing that'll keep it off the road right now though
Good to be riding again, I was having a great time on the test ride and then getting it home.
Chillin
heat and concrete don’t mix too well, don’t ask me how i know.Ta - 100 C was OK, I took care to direct the hot air into open space at the center of the box. So far the cardboard is looking a little dried out but that's about it.
Might be an idea to put the box on a concrete floor and well away from anything else though, I really should have thought of what I'd do if it started going wrong
suspect water absorbed by concrete turns to steam......
READ AND UDESTAND
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