slaw1967 Posted March 14, 2009 Share Posted March 14, 2009 I have just bought a 1989 yb100 and when riding if i give it more throttle up a slight hill it wont go and feels like its dying so i had a word with local yammy dealer who revved it up and said it looked like baffles were blocked. So i removed them and they looked ok so i burned them off and re-fitted. I also checked oil pump setting and that was correct. So i then took it out again and the problem is still there. But when it feels like its dying if i drop the clutch it revs its pants of so i dont think its a blocked baffle. Also if i drop down the gears and then thrash it it seems to go again. Could it be fuel starvation or a breakdown on the ignition side (new spark plug fitted). If anyone can anyone shed any light on it i would be very greatful. Thanks Simon. Link to comment Share on other sites More sharing options...
fosdyke Posted March 15, 2009 Share Posted March 15, 2009 I have just bought a 1989 yb100 and when riding if i give it more throttle up a slight hill it wont go and feels like its dying so i had a word with local yammy dealer who revved it up and said it looked like baffles were blocked. So i removed them and they looked ok so i burned them off and re-fitted. I also checked oil pump setting and that was correct. So i then took it out again and the problem is still there. But when it feels like its dying if i drop the clutch it revs its pants of so i dont think its a blocked baffle. Also if i drop down the gears and then thrash it it seems to go again. Could it be fuel starvation or a breakdown on the ignition side (new spark plug fitted). If anyone can anyone shed any light on it i would be very greatful. Thanks Simon. Hi Simon Had similar prob on my YB which turned out to be carb problems. You say you have checked the oil pump setting have you checked all the carb settings, and taken it out thoroughly cleaned it and blown out all the airways? If you've just bought it you could have ignition problems - have a look at the surfaces on the points if they are particularly black you could have a condensor failure - though this is rare. If they are pitted you might need to replace them. The ignition timing is fiddly to set up on the YB without a dial test gauge but you can improvise with a piece of dowling and a protractor! Check everything out and see if it improves - I got a new set of points from fleabay for about £4. Good luck Link to comment Share on other sites More sharing options...
JimR Posted March 15, 2009 Share Posted March 15, 2009 Hi Simon Had similar prob on my YB which turned out to be carb problems. You say you have checked the oil pump setting have you checked all the carb settings, and taken it out thoroughly cleaned it and blown out all the airways? If you've just bought it you could have ignition problems - have a look at the surfaces on the points if they are particularly black you could have a condensor failure - though this is rare. If they are pitted you might need to replace them. The ignition timing is fiddly to set up on the YB without a dial test gauge but you can improvise with a piece of dowling and a protractor! Check everything out and see if it improves - I got a new set of points from fleabay for about £4. Good luck Another thing to check is the silencer and exhaust port for carbon, If the mechanic at the shop was good he would have detected that decarbonization was needed and gone for the easy option, with certain YB's the oil pump minimum stroke was set inncorrectly at the factory I would guess these have been put right by now (but you never know !), but it would be worth a check if you havent already done so. Regards Jim Link to comment Share on other sites More sharing options...
VonR Posted April 19, 2009 Share Posted April 19, 2009 I had similar but not exact problems with a YB100 that I aquired last year - in fact I posted the problem on this site. Again, I started with the baffle - but made no difference. It was a combination of things in the end: a) Rust inside fuel tank internittently blocking fuel tap, pilot & main jets - the solution was to use a tank lining kit - I used the POR15 kit from the FROST auto restorer's catalogue. Also fitted an in-line feul filter. Float height was wrong - in my case, allowing too much fuel in (on the occasions when tap and jets weren't blocked) c) Changed grade of spark plug to NGK B7HS - it was running a B7RS (or something with an R in - chucked it away, so can't confirm) d) Ignition timing was slightly out - so corrected that e) Exhaust was blowing slightly through both of the joints - so sealed those up with exhaust putty. Now pulls hard and revs well in all gears (bit tinny when cold but I suppose that's normal) Brgds, Ian Link to comment Share on other sites More sharing options...
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