bassbill Posted June 30, 2010 Share Posted June 30, 2010 Hi there After 20 non biking years I just bought a used XV 535. When i first tested the bike it had a pair of slashed open pipes fited on, and I noticed that the rear drum brake area was a bit black, obviously due to rich mixture running. The engine was running ok though when took it for a ride. It was very noisy, so I asked the dealer to fit a set of new mufflers, regular ones to reduse the noise, so he did. After that, the engine misfires badly. Looks like it is running on a single cylinder, the back one, and it won't rev up no matter if I open the throttle full open. This happens when riding. I changed the spark plugs but did not help at all. The old spark plugs came out black and dry. My guess is too rich mixture, but the problem seems more like an electrical one. With the bike standing, I can probably manage to rev it up, but it is still not responding to throttle and messes up for a few seconds before startin to rev up but very rough running anyway. Any suggestions please Link to comment Share on other sites More sharing options...
Ttaskmaster Posted July 1, 2010 Share Posted July 1, 2010 Try adjusting the mixture. Get a Colortune kit and make use of that to get the cylinders approximately balanced. Have the rear cylinder slightly leaner as that one gets less air cooling. If that doesn't sort it, have it properly tuned by a trusted professional. Also: Another option may be putting different jets in the carb. You didn't mention whether the dealer actually did this. I'd be willing to bet that when the slash-cuts were put on, the jets were changed out to compensate. If the dealer just swapped the silencers, you probably have the wrong jets and hence too much fuel. If all this still doesn't sort it, check the exhaust for gaps and holes, either from rust or simply improper fitting. Link to comment Share on other sites More sharing options...
bassbill Posted July 1, 2010 Author Share Posted July 1, 2010 Thanks for the advice. I got the bike to a pro already, and he replied to me that the problem seems to be the carburators diaphragms. Said to me that they were damagded and the P.O. tried to repair them with silicone. What would you say about it? Link to comment Share on other sites More sharing options...
Ttaskmaster Posted July 1, 2010 Share Posted July 1, 2010 Possibly... Assuming the layout is similar to the Dragstar: Look under the tank, between the two cylinders. There should be a pair of thick, stumpy rubber tubes going, one from each cylinder, up into the carb unit. If these are cracked to buggery, then he's probably right. Diaphragms, hoses, manifolds.... there are seemingly a hundred names for these little rubber bastards! However, if these are damaged/perished* enough to allow extra air in, then this will account for your bike running funny and stuttering a lot. IF this is the case, then these will need replacing. Expect about £80 for a brand new pair. *Rubber does perish over time anyway. Link to comment Share on other sites More sharing options...
YPVS TONE Posted July 1, 2010 Share Posted July 1, 2010 I have found an old Yamaha Technical service bulletin that was sent out to Yamaha dealers in the UK. Model : XV535 Subject : Ignition Failure Symptoms - Engine will not start,misfire or cuts out. Cause - We have found on some machines that this failure is caused by corosion of the joint for the red/white power feed wire to the HT coil,inside the main wiring harness. This can also effect the functioning of the fuel pump relay and cause the relay to "buzz" when the ignition is switched on to the on position. Remedy - Strip back the outer sheathing of the wiring harness as far as the joint for the red/white wire. If this joint is found to be corroded,repair and solder the joint. Replace the sheathing or tape up the wiring harnes to stop water entry. There is also a picture that shows the red/white power feed wire just above the front cylinder in the main harness. Hope this helps. Tony. Link to comment Share on other sites More sharing options...
KirriePete Posted July 2, 2010 Share Posted July 2, 2010 Possibly... Assuming the layout is similar to the Dragstar: Look under the tank, between the two cylinders. There should be a pair of thick, stumpy rubber tubes going, one from each cylinder, up into the carb unit. If these are cracked to buggery, then he's probably right. Diaphragms, hoses, manifolds.... there are seemingly a hundred names for these little rubber bastards! However, if these are damaged/perished* enough to allow extra air in, then this will account for your bike running funny and stuttering a lot. IF this is the case, then these will need replacing. Expect about £80 for a brand new pair. *Rubber does perish over time anyway. Err, sounds like the actual carb operating diaphragms to me, the thin rubber in the carb tops that operates the slides. Only takes a slight leak here and the slides don't, errr, slide - also if they been bodged repaired with silicone they'll be too thick/heavy to operate correctly. New replacements, £32 each from NRP - Clicky Linky Thing. You're welcome Link to comment Share on other sites More sharing options...
bassbill Posted July 5, 2010 Author Share Posted July 5, 2010 Err, sounds like the actual carb operating diaphragms to me, the thin rubber in the carb tops that operates the slides. Only takes a slight leak here and the slides don't, errr, slide - also if they been bodged repaired with silicone they'll be too thick/heavy to operate correctly. New replacements, £32 each from NRP - Clicky Linky Thing. You're welcome Hi there KirriePete. I actually think that this is the case. My mechanic checked the carbs and the slide diaphragms were useless. Actually there were several splits on the membrane, and at some point someone tried to repair them with silicone, and we all know what this means. Here are some pics of the situation as is right now. Link to comment Share on other sites More sharing options...
KirriePete Posted July 5, 2010 Share Posted July 5, 2010 Hi there KirriePete. I actually think that this is the case. My mechanic checked the carbs and the slide diaphragms were useless. Actually there were several splits on the membrane, and at some point someone tried to repair them with silicone, and we all know what this means. Here are some pics of the situation as is right now. Yeah, looks like a call to NRP for you ... PS - What is it with Zshare and the 45 second wait? Makes it a real pain in the ar$e to view any pics online, and as for embedding .... sheesh! Here's your pics dropped into my photobucket account, much easier if you ask me... Is that silicone? Looks like Araldite to me, and I should know, I keep the share price of that company abnormally high! Link to comment Share on other sites More sharing options...
bassbill Posted July 6, 2010 Author Share Posted July 6, 2010 Absolutely right about the photobucket My mechanic told me that he already managed to find a pair of diaphragms for a fair price in Greece. But I guess that your link is always gonna be usefull in the future, cause the carbs always seem to need bits & pieces. As soon as fitted and tested I 'll post again to tell you what happened. May take more than a week though cause right now I'm in vacation in the western part of Greece. With my car as you can tell, but thank God it's as close to a bike as it gets... It's a Miata. Link to comment Share on other sites More sharing options...
bassbill Posted July 14, 2010 Author Share Posted July 14, 2010 Updating. New diaphragms fitted, and things seem to be a lot better, but still not perfect. I guess it's due to the smaller jets fitted in the previous situation trying to sort things out. I wii fit the normal jets tomorrow mornig and we 'll see. Bike runs o.k, just it does not rev up very happily. No misfires though... Big inprovement in general I would say. Link to comment Share on other sites More sharing options...
bassbill Posted July 15, 2010 Author Share Posted July 15, 2010 Update II Old jets #135 fitted. Needles readjusted to position 1 ( they were on pos 3, from 5), and the improvement is really there. There is some backfire there though that was not there before. Any ideas. I know I should search the forums but no time indeed. I am taking the bike for a 50 Km run this afternoon to see how it operates in the open road. Link to comment Share on other sites More sharing options...
Paulwhite Posted July 15, 2010 Share Posted July 15, 2010 Update II Old jets #135 fitted. Needles readjusted to position 1 ( they were on pos 3, from 5), and the improvement is really there. There is some backfire there though that was not there before. Any ideas. I know I should search the forums but no time indeed. I am taking the bike for a 50 Km run this afternoon to see how it operates in the open road. put the needle on position 3 (think its the standard original position) but should sort it out Link to comment Share on other sites More sharing options...
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