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Adjusted idle screw, now bike wont run

socci

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Hello, my bike over the last few weeks has been dying at idle. It ran fine all season until now. I adjusted the idle screw and it seemed to work, but when I took it out the RPMs kept getting hung up at 3000 when in gear. They would not fall until I reved it in neutral. I currently have the bike setup to idle at 1200ish and it is fine until the bike starts moving. This is weird but even when still in neutral if I start coasting down hill the bike surges to 3000 rpms. The RPMS will not drop back to idle unless I rev the throttle a few times. Also one of the exhaust pipes is smoking while running. Not too bad but its noticeable. Lastly when I was attempting to ride the bike after the adjustments I am getting a loud pinging noise only when in gear.

Appreciate the help.
 
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At the very least the carbs need cleaning. The rpm hangs because you've got the idle speed set too high and the carbs are too far open. Only thing about that is when you lower the idle then it won't idle. Opening all 4 carbs too much because one is clogged does not work.

Carbs or engine condition and likely valve clearances or sealing. The oil burning is valve seal most likely, these are well known for it.

People distress when it won't idle right, then they go for carbs first thing and wrong, wrong, wrong. The valves are the issue much of the time and why knowledgeable people commonly buy these to then set the valves really well, and redo the carbs for all the screwups rather anything being wrong with them then ride the formerly crap running bikes frever and they run fine.

The carbs DO have a bad habit of clogging up the idle feeds though but most clean them and they're still not right. Especially the ones with pressfit pilots, there are mixture passages above them that cannot in any form be gotten to to clean.
 
At the... .

Thank you for that info, very helpful. Since my post I found large air leaks at the manifold boots. I am having a hard time getting the carbs to sit in the rubber deep enough to clamp them without a leak. I am hoping this leak could be the solution to my problem, is that a possibility?
 
Entirely, hanging idle above all things must have available air in some fashion to do so.

Be very suspect that if carb bank is trying to fall off boots it is not in far enough past the ridges cast in that hold it in place. Older harder boots do that very commonly. Old ones are almost impossible to get all the way in. As well stretching them when hard puts cracks in them that never will seal without new parts.
 
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