Page 34 of 46 FirstFirst ... 24323334353644 ... LastLast
Results 496 to 510 of 680

Thread: Winter Layup - 1995 Ducati 900 Supersport

  1. #496
    Join Date
    28th January 2015 - 16:17
    Bike
    2000 Ducati ST2
    Location
    Lower Hutt
    Posts
    1,274
    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.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	IMG_0813.JPG 
Views:	41 
Size:	378.4 KB 
ID:	332599   Click image for larger version. 

Name:	IMG_0820.JPG 
Views:	29 
Size:	442.1 KB 
ID:	332597   Click image for larger version. 

Name:	IMG_0818.JPG 
Views:	30 
Size:	496.4 KB 
ID:	332598   Click image for larger version. 

Name:	IMG_0834.JPG 
Views:	26 
Size:	372.9 KB 
ID:	332600   Click image for larger version. 

Name:	IMG_0832.JPG 
Views:	25 
Size:	373.1 KB 
ID:	332601   Click image for larger version. 

Name:	IMG_0831.JPG 
Views:	24 
Size:	377.9 KB 
ID:	332602  

  2. #497
    Join Date
    28th January 2015 - 16:17
    Bike
    2000 Ducati ST2
    Location
    Lower Hutt
    Posts
    1,274
    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.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	IMG_0838.JPG 
Views:	54 
Size:	463.2 KB 
ID:	332615   Click image for larger version. 

Name:	IMG_0841.JPG 
Views:	51 
Size:	552.5 KB 
ID:	332613   Click image for larger version. 

Name:	IMG_0839.JPG 
Views:	43 
Size:	477.3 KB 
ID:	332614   Click image for larger version. 

Name:	IMG_0837.JPG 
Views:	42 
Size:	430.5 KB 
ID:	332616  

  3. #498
    Join Date
    3rd February 2004 - 08:11
    Bike
    1982 Suzuki GS1100GK, 2008 KLR650
    Location
    Wallaceville, Upper hutt
    Posts
    5,049
    Blog Entries
    4
    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/viewto...KLR650#p487227
    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)

  4. #499
    Join Date
    28th January 2015 - 16:17
    Bike
    2000 Ducati ST2
    Location
    Lower Hutt
    Posts
    1,274
    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-super...ide-carbs.html

  5. #500
    Join Date
    28th January 2015 - 16:17
    Bike
    2000 Ducati ST2
    Location
    Lower Hutt
    Posts
    1,274
    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.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	IMG_0844.JPG 
Views:	20 
Size:	499.0 KB 
ID:	332634   Click image for larger version. 

Name:	IMG_0845.JPG 
Views:	17 
Size:	387.8 KB 
ID:	332635  

  6. #501
    Join Date
    28th January 2015 - 16:17
    Bike
    2000 Ducati ST2
    Location
    Lower Hutt
    Posts
    1,274

    Several topics, long post

    Been clocking a few hours up in the garage over the last few days, covered quite a bit of ground while trying to sort out what's happening with the rough running.

    First, I tried the usual 3,000 mile service, paying particular attention to valve clearances in case these were contributing to running problems. They've all loosened up a bit, probably due to the MBP retainers crushing up by a thou or two. I also found a hose clamp sitting skewed on the horizontal cylinder's carburettor output, enough to cause a minor vacuum leak. This might have been why spark plugs from this cylinder were coming out bone-white. The AFR gauge is on the vertical cylinder exhaust and wouldn't have shown a lean mixture on this cylinder.

    Along the way I found out something unpleasant about the Taiwanese-made, plastic quick release fuel line couplings: sometimes they leak. It's fixable. If the 7 x 1.5 O-ring is carefully lifted out, the flash line from the mould can be seen to run right through the O-ring's inner crush diameter. Some very careful work with a needle file can smooth this out and then it's OK. That said, these fittings are OK but not great, if someone can recommend a better alternative then I'd appreciate a heads-up.

    Anyway... went out for a ride, no improvement whatever. Damn. Back to the garage.

    I got the oscilloscope out again and spent much of a sunny afternoon annoying the neighbors. About the only usable result from the photographs is shown below. There seemed to be a lot of trouble with reliable triggering, connecting lead wires to plugged-in pickups, etc etc... but in the end I think I have a result. The horizontal cylinder pickup coil looked OK when tested unplugged, with the motor cranked by the starter, but as soon as the CDI was plugged in and the ignition energised it would not generate any significant signal. The vertical cylinder pickup worked just fine regardless.

    As a last resort I tried something I'd read of on the Ducati.ms forums - I fitted braided shielding to the pickup cable. Some people out there have been keen enough to fit shielding right through the gland and into the engine; for the purpose of testing (and sanity) I stopped at the crankcase. The shielding is pure braiding and heatshrink, there's no solder connections between the legs or to the lead wire used to ground the braid. Oxidation will kill it in a season or less, but for testing it'll do.

    I tried this tonight and was surprised to see how much of a difference it makes: the bike is perceptibly smoother and sounding better, even just revving it on the stand with the exhausts pointing out of the garage. To carry to the test as far as possible, I took the strobe gun and tried it on both cylinders.

    What a difference. The vertical cylinder idles at the reference mark and advances cleanly to the full mark, with the strobe gun keeping pace the whole way. There were no missed flashes, unlike previously.

    The horizontal cylinder was the same story as before, though. The idle is off the reference dot, with the engine a few degrees advanced already, and the strobe gun dropped out as soon as RPMs were increased.

    I also borrowed a 100V Megger from work and tested the pickup coils insulation resistances to ground. Neither failed, but the test that was really needed was seeing output from the pickup under real operating conditions - i.e. in ac voltage generation, with the coil loaded as it would be in normal use - and the oscilloscope work covered that already.

    The conclusion I'm now operating on is that the horizontal cylinder pickup coil is stuffed. The shielding was a very worthwhile improvement and I'd recommend doing this on any old bike running inductive pickups and plain cabling. It can't rescue damaged components, though.

    As to why the pickup coil has failed - my best guess is that inside an engine, this is inevitable given enough time. Heat, oil (with acidic combustion byproducts in it), vibration, plus constant electrical loading of what's probably very fine coil wire, it'll add up after 22 years. Either the insulation has been damaged by the oil and heat, or the wire has thinned somewhere and can't carry the load any more, even though the resistance still tests fine on the multimeter.

    I also had a look at the Hayne's manual, courtesy of my local public library. I'm not so keen on buying one anymore. There's very little useful information in there for someone in my situation, when Haynes write their manuals they rebuild a near new bike instead of a high mileage and old one.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	IMG_0855.JPG 
Views:	13 
Size:	314.1 KB 
ID:	332667   Click image for larger version. 

Name:	IMG_0876.JPG 
Views:	21 
Size:	557.9 KB 
ID:	332666   Click image for larger version. 

Name:	IMG_0877.JPG 
Views:	31 
Size:	460.4 KB 
ID:	332665   Click image for larger version. 

Name:	IMG_0878.JPG 
Views:	19 
Size:	435.7 KB 
ID:	332670   Click image for larger version. 

Name:	IMG_0880.JPG 
Views:	26 
Size:	441.0 KB 
ID:	332669   Click image for larger version. 

Name:	IMG_0883.JPG 
Views:	26 
Size:	595.1 KB 
ID:	332668  

  7. #502
    Join Date
    3rd February 2004 - 08:11
    Bike
    1982 Suzuki GS1100GK, 2008 KLR650
    Location
    Wallaceville, Upper hutt
    Posts
    5,049
    Blog Entries
    4
    Seeing as you have one good cylinder and one bad one, can you not swap components one at a time until the problem moves?
    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)

  8. #503
    Join Date
    28th January 2015 - 16:17
    Bike
    2000 Ducati ST2
    Location
    Lower Hutt
    Posts
    1,274
    Quote Originally Posted by pete376403 View Post
    Seeing as you have one good cylinder and one bad one, can you not swap components one at a time until the problem moves?
    Yep, that'd be the normal procedure, but I don't think I'd have picked which pickup coil it was by doing that. It's also hard work - I'd have to get inside the cases to swap the pickup coils over, if that's even possible with made-to-length wiring like they use.

    The other thing is that nothing's actually stone cold dead. It's just that stuff has slowly gotten a bit sick. If it 100% didn't work then it'd be very possible to swap things over and see if moving something brought a dead cylinder back to life. It isn't like that though, it's still running on both, it's just that it's running really badly.

    I'd always thought that the horizontal cylinder was running fine while the vertical struggled, it took using an oscilloscope and the strobe gun to show it was actually the other way around.

    I'm happy with the result I got, order to Stein Dinse is already away.

  9. #504
    Join Date
    20th January 2008 - 17:29
    Bike
    1972 Norton Commando
    Location
    Auckland NZ's Epicentre
    Posts
    3,554
    Liam has those too.

    http://www.fastbikegear.co.nz/index....oducts_id=6792

    I haven't bought any bits of Stein Sinse for a while but I gather their minimum post was pricy.

    You can really chase your tail with ignitions/carbs. I spent a lot of time getting my Mk2 lemans sorted even swapping carbs from one side to the other,

    only to find most of the brass worn....but no enough that you could see it.

    Ignitions are the same, replace the lot.
    DeMyer's Laws - an argument that consists primarily of rambling quotes isn't worth bothering with.

  10. #505
    Join Date
    28th January 2015 - 16:17
    Bike
    2000 Ducati ST2
    Location
    Lower Hutt
    Posts
    1,274
    Quote Originally Posted by Voltaire View Post
    Liam has those too.

    http://www.fastbikegear.co.nz/index....oducts_id=6792

    I haven't bought any bits of Stein Sinse for a while but I gather their minimum post was pricy.

    You can really chase your tail with ignitions/carbs. I spent a lot of time getting my Mk2 lemans sorted even swapping carbs from one side to the other,

    only to find most of the brass worn....but no enough that you could see it.

    Ignitions are the same, replace the lot.
    FastBikeGear: check the little "available stock" tag before buying. I've been keeping tabs on those pickups and they seem to have been on order for over a year... No stock in country. Currently I'm waiting on a few components to be machined up for the upgrade to Ignitech & Hall Effect, and it's been 5 weeks since order placement now.

    In the meantime Stein Dinse charge 40 euros for postage regardless of order size, so you're right, it's not exactly free, but they've been very reliable in terms of getting goods to me in a few weeks. Summer is just around the corner. It's wasteful buying two complete (separate) ignition systems, but I've learned the hard way about open-ended waiting times on orders.

    In terms of fault finding and tail-chasing - I agree, once the bike's 20+ years old and you start having hard-to-trace problems with running, you can really chase your tail with this stuff. Swapping old components around really only works if there's a large difference between them.

    After the work I've been through over the last few years with the Ducati's running problems I also agree with the idea of replacing the lot in one go. 20+ years old... as soon as one ignition component is known walking wounded, the others aren't far behind. It'd have been horribly pricey to do the whole thing in one hit but I'd have saved maybe a couple of hundred hours in the garage, not to mention rides spoiled or cancelled. Hell, chances are that the bike's been plagued with bad ignition since I bought it and I've simply never seen one running properly to compare it against.

    I've been there with worn brass in carburettors as well, had that with the original Mikunis emulsion tubes going oval around the needles. I was lucky enough to be able to see it by eye, but it wouldn't have been easy to measure with normal garage tools unless a set of 0.1 stepped drills was available as plug gauges.

    All that said, what I tried in the few posts above was a way to diagnose ignition systems without swapping anything and without spending a fortune. A 'scope, probes, and a strobe could be had for around $200 (there's a few oscilloscopes floating around on TM these days). Between the oscilloscope and the strobe gun, I've seen that the system has a problem with radio frequency interference (and probably always has) and that a pickup coil can test just fine according to all the workshop manuals and yet still have issues when running. So I think this stuff is worth doing.

  11. #506
    Join Date
    28th January 2015 - 16:17
    Bike
    2000 Ducati ST2
    Location
    Lower Hutt
    Posts
    1,274
    Replaced the pickup coils. Pretty straightforward really, just a couple of notes for anyone else doing similar.

    - The cover removal tool is necessary, so is taking the kickstand bracket off since it'll foul the cover otherwise.

    - The pickup wires can be pulled out of their box headers (at the CDI's) by using a fine flat-bladed jeweller's screwdriver. You don't need the specific Ducati tool.

    - Before doing this (apologies for the caps) LABEL EVERYTHING. H for horizontal, V for vertical, red, white, yellow, black. Get the sharpie out and label headers. It's very easy to swap things around by mistake on reassembly.

    - Ducati labelled wiring colours inside the engine covers, which was a nice feature. There's also an offset scale cast into the pickup coil mounting bracket, I think each tooth marks 2 degrees.

    - Ducati's OEM pickups come with good wiring and cabling, it's why I chose these over the aftermarket. There's a proper moulded-on silicone rubber hose to go through the gland, for example.

    - I used an impromptu feeler gauge made out of a few bits of brass shim, taped together at the specified 0.7mm +/- 0.1 clearance. The reason for brass was that it's not affected by magnetic pickups, the reason for the clearance (when I've run tighter in the past) is that pickup coil voltage increases with RPM and I didn't want to run a risk of damaging CDI circuitry.

    - Unfortunately it'll take a few goes back and forth to get pickup clearance right, this will involve turning the engine over a couple of times and loosening and retightening the bracket bolts.

    - it's easy to skew or cross-thread the cable gland retainer on reassembly. It'll feel like it's compressing the rubber washer and ensuring a seal, but it's just crossed. Keep an eye out for this and check it's parallel on reassembly.

    Anyway, I got everything back in place, fitted new shielding (but only over half the cabling, up to the Y split - more about this later), fired up and the bike started without issues.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	IMG_0973.jpg 
Views:	29 
Size:	170.8 KB 
ID:	332847   Click image for larger version. 

Name:	IMG_0975.jpg 
Views:	23 
Size:	144.1 KB 
ID:	332849   Click image for larger version. 

Name:	IMG_0976.jpg 
Views:	30 
Size:	159.7 KB 
ID:	332846   Click image for larger version. 

Name:	IMG_0977.JPG 
Views:	24 
Size:	748.6 KB 
ID:	332845   Click image for larger version. 

Name:	IMG_0979.JPG 
Views:	23 
Size:	762.7 KB 
ID:	332848   Click image for larger version. 

Name:	IMG_0980.jpg 
Views:	25 
Size:	142.9 KB 
ID:	332850  

  12. #507
    Join Date
    28th January 2015 - 16:17
    Bike
    2000 Ducati ST2
    Location
    Lower Hutt
    Posts
    1,274
    Carrying on with the issue of rough running... I'd taken the bike out for a quick spin after pickup coil replacement and the vibration hadn't got better. It was worse.

    What to do, what to do... after some thinking, I pulled the spark plugs to check combustion and found them black. Bike's running super rich. Bike's also very, very loud. This has happened before, and I remembered that I haven't repacked the mufflers in a long time. On checking the maintenance logs, it hasn't been done since the engine rebuild (at least), and that was 14,000 miles ago.

    Getting into the cans is pretty straightforward, the photos tell most of the story. A couple of pin punches helped with the rivets, the little one is for knocking the center pin through before drilling.

    The packing has thoroughly filled up with carbon. I'm not sure if this is normal or indicates vastly rich tuning - anyone? Anyway, the experience has been that this affects engine behaviour quite strongly, and I'm thinking that it makes sense to schedule a re-pack at every other oil change.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	IMG_0990.jpg 
Views:	26 
Size:	263.0 KB 
ID:	332853   Click image for larger version. 

Name:	IMG_0994.jpg 
Views:	24 
Size:	142.5 KB 
ID:	332852   Click image for larger version. 

Name:	IMG_1000.jpg 
Views:	23 
Size:	126.6 KB 
ID:	332851   Click image for larger version. 

Name:	IMG_1001.jpg 
Views:	23 
Size:	155.3 KB 
ID:	332856   Click image for larger version. 

Name:	IMG_1003.jpg 
Views:	27 
Size:	160.4 KB 
ID:	332854   Click image for larger version. 

Name:	IMG_1005.jpg 
Views:	21 
Size:	163.1 KB 
ID:	332855  

  13. #508
    Join Date
    28th January 2015 - 16:17
    Bike
    2000 Ducati ST2
    Location
    Lower Hutt
    Posts
    1,274
    Mufflers repacked. Went for a test ride, bike ran better, vibration issue's still there but has roughly halved.

    Just a quick note about using the crowbar to get the end caps off - don't do this on shiny new mufflers - the crowbar and mallet technique has a distressing habit of jumping and biting. I've put a few fresh scratches onto the stainless piping and outlet. It's not the end of the world with these battered stock mufflers, but it'd suck to have this happen with nice new ones.

    So, next step - is there dirt in the carburettors, with one cylinder running lean or rich? So I pulled the carburettors off for an external wash prior to blowing carb cleaner through the jets.

    External washing was done on the cheap, with an old paintbrush, a laundry sink filled with warm water and dishwashing liquid, and inlet and outlet pipes masked off with gloves and stretch ties to prevent water ingression. I didn't submerged the bodies, just held them above the water. Dishwashing liquid was used because I knew it wouldn't hurt the aluminium, I've found that a lot of the more aggressive degreasers around will tend to attack the metal if they're on for too long. There was some dirt under the inlet trumpets and it was getting close to the slow air jets and main air jets, despite claims that gaskets are only needed for ram air applications, I think it's probably a good idea to seal these to the bodies properly if possible.

    The insides turned out to be surprisingly clean considering the mileage. It was when I'd unscrewed the slow air jets and the idle mixture adjustment screws that I found the misadjustment, and the reason for it... the idle mixture adjustment on the horizontal cylinder was nearly screwed all the way in. The startup carb bowl heater element was sitting very high in the carburettor bowl well. I think vibration had been working to push this heater upwards. It had then been hitting the screw and bumping it.

    The heater can push the screw, it can't pull on it, so over time it'll force the adjustor further and further upward. This is entirely due to my rough build. There's a retainer plate to stop the heater element falling down. There isn't anything to clamp that element securely in place, or prevent it moving upwards. I'm going to have to modify.

    Anyway... carburettors back onto the bike (the quick release fuel hoses helped greatly with this) and test rode again. Further improvement, still hasn't fixed the problem though.

    At this point I went and had a look at interference in the ignition system again and finally noticed something I should have seen much earlier: I'd routed the HT leads within a couple of centimeters of the horizontal cylinder's CDI unit. This isn't good practice as far as RFI interference and cross-talk goes. I re-routed as per the photos, cable ties to the coil mounting brackets and split fuel hose to help cushion the HT leads. It's an improvement of only 3 to 4 centimeters, but at this point every bit helps.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	IMG_1011.JPG 
Views:	17 
Size:	757.3 KB 
ID:	332931   Click image for larger version. 

Name:	IMG_1012.JPG 
Views:	20 
Size:	696.9 KB 
ID:	332930   Click image for larger version. 

Name:	IMG_1014.jpg 
Views:	19 
Size:	128.3 KB 
ID:	332929   Click image for larger version. 

Name:	IMG_1015.JPG 
Views:	18 
Size:	759.9 KB 
ID:	332934   Click image for larger version. 

Name:	IMG_1017.JPG 
Views:	22 
Size:	677.8 KB 
ID:	332933   Click image for larger version. 

Name:	IMG_1018.JPG 
Views:	17 
Size:	715.9 KB 
ID:	332932  

  14. #509
    Join Date
    28th January 2015 - 16:17
    Bike
    2000 Ducati ST2
    Location
    Lower Hutt
    Posts
    1,274
    A bit more work on RFI shielding for the ignition system - I'd tried this earlier, with some success, before changing the ignition pickup coils. One of the issues with getting the old shielding off had been that I'd used adhesive-lined heatshrink to fit the braided sleeving. It went on fine; it was a nightmare getting it off again. This time the construction was:

    - Unshrunk tubing under the braid, to protect the pickup coil wiring against loose strands from the braid
    - the braid itself
    - sparkie's tape to secure braid ends to the undertube
    - auto wire, stripped and wrapped around the braid, to make the electrical connection
    - more sparkie's tape over that to wrap the, ahem, 'connection'
    - high temperature plastic overbraid
    - yet more sparkie's tape over the ends of the overbraid

    Apologies, the photos are out of order - look at filename numbers for the sequence.

    The Y-split complicated things, and I didn't quite have enough braid to properly cover the joint. Shields need to be as close to continuous as possible. Note that there aren't multiple grounds - the wires come back to one point on the shield and then are earthed to the frame by one link only. This is to prevent loops forming in the shield and thus turning the braid into a pickup and an antenna, coupling noise in more effectively than if there was nothing there at all.

    It's not going to last. Weathering, heat and vibration will kill this within a year. The point to this is to see what effect it has, and then if it works, to make something durable along the same lines.

    Short answer: it helps, but it's not a complete shield. I haven't got anything over the CDI's or the lines to them, for example. Slight improvement when running.

    During my reading about shielding, I turned up this PDF:

    http://www.analog.com/media/en/techn...doc=CN0397.pdf

    It gets very technical and it raised a lot of thoughts... first of which is that the layout of the ignition components on the Supersport really isn't the best. Coils are placed immediately next to CDI's. Pickup wiring is run close to HT leads, in the original setup. That sort of thing. It packages nicely. I don't tend to see Japanese bikes laid out like this, the CDI is usually under the seat, while the coils are close to the engine.

    One of the basics of avoiding interference gremlins is that distance is your friend. Get as much separation between components as possible.

    Another issue that the PDF raised was the possibility of magnetic interference from the coils themselves - like most ignition coils, they run open laminations, so there's a free magnetic field around them. This is much harder to screen out than high-frequency RFI - a dinky piece of nickel-plated copper braid simply won't do all that much. The paper pointed out that steel is the best material, and it's got to be reasonably thick to get any sort of attenuation. Several millimeters thick. The bright side to this is that I don't need that much attenuation (a few dB would be enough) to get an improvement.

    Something else I'd read concerned the idea of using braided shielding on HT leads. It's been tried, off and on, for well over forty years. Short answer: it starts out well enough, but any degradation in the HT lead insulation and the shielding turns the lead into a capacitor. Spark starts being lost to the shield. The second problem is that the shield itself, if connection to engine ground is lost, will run at full HT voltage. This can be lethal. Basically, don't shield the HT lines, shield everything else.

    So the bit that I'd like to try next with this is to make up some sort of steel shielding for the pickup lines, where they run close to the ignition coils, and a pair of steel boxes for the CDI's. Everything will have to be grounded to one common point, so there's be a secondary network of wiring as well.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	IMG_1021.JPG 
Views:	20 
Size:	727.6 KB 
ID:	332941   Click image for larger version. 

Name:	IMG_1020.JPG 
Views:	18 
Size:	713.5 KB 
ID:	332942   Click image for larger version. 

Name:	IMG_1022.JPG 
Views:	20 
Size:	762.0 KB 
ID:	332940   Click image for larger version. 

Name:	IMG_1019.JPG 
Views:	20 
Size:	736.6 KB 
ID:	332943  
    Last edited by OddDuck; 17th October 2017 at 07:12. Reason: Photo notes

  15. #510
    Join Date
    3rd February 2004 - 08:11
    Bike
    1982 Suzuki GS1100GK, 2008 KLR650
    Location
    Wallaceville, Upper hutt
    Posts
    5,049
    Blog Entries
    4
    Run the wires through a steel tube? Does it have to be steel? Would copper -easier to bend- do it?
    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)

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •