Guys my MC18 has trouble on idling, not as if it dies on idle but it idles at about 4000 RPM.

just to clarify the problem... Upon starting the engine it will run ok and idles at about 1500 RPM. but when I rode it for a while and stop, put it in neutral and lets it idle, it rises at 4000 rpm.. it feels like sometings stuck or what... it sometimes happen and sometimes not...

anyone have an idea on how to fix it?

If you are really lucky, like I was when I had this happen a while back, it is just a matter of your idle being set a touch too high. I found that if the idle was set at 1500-1600 (or higher), that it would sometimes hang up at 3-4k RPM when I came to a stop (or even if I just blipped the throttle). Turned idle down to 1250-1300 and problem solved. Thanks to Matt for that tip, so if it works for you, thank him. An alternative is an air leak, but that's another (less happy) story. Actually, re-reading your description more closely, if it rises to 4k after being at 1500, that would be different from what I had. Mine would not come down from higher RPM once I revved it. Still, it's worth a try to set the idle a little lower. Oh well, I tried. Good luck.
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-Jim
'93 MC21

Jim,

when my bike rises it its idle at 4K RPM, it also wont go down unless I turn the engine off and leave it for a long time but if I turned it off then run it again, it will still be at 4K idle..

by the way, if its an air leak problem? where can it possibly be? in the tubes of the carburators?

czsphl wrote:Jim,

by the way, if its an air leak problem? where can it possibly be? in the tubes of the carburators?

Crank seals, $$$$$$$$$$$$$$
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