1981 K4 idle problems

[browndog]

I bought a 750 recently that was, according to the seller, in "Pristine" condition.  However, it has a problem with the idle I have found.  Even after the bike is warm it will die if it sits at idle for around 30 seconds.  Also, after driven for a while, the idle periodically will stay at 1500 rpm to 2000 when I come to rest -- I then have to let the clutch out quickly and jump the bike and it may or may drop the idle.  

I took the bike to a motorcycle mechanic and, after cleaning the carburetor, he could not find a solution.  I asked if the carbs needed to be rebuilt but e said everything looked fine with the carburetor (I would have no idea).

The bike's compression is fine and it does have an inline fuel filter.  New plugs as well.

Any ideas would be appreciated?

Thanks,

Dan

[swiffer]

You would think the mach would have checked the idle.Have you looked under the carb.There is a black knob on mine that sets the idle {On mine the idle is 1000 +/- 100 rpm.}

[dylansdad022102]

sounds like a sync problem to me.try syncing your carbs. i had the same problem with my cb turned out i had a cut in one of my boots and the carbs were way out of sync. some silicone and a carb sync she purrrrrs like a lion lol. i would of said kitten but with the full kerker and k&n filter its more like a purring lion now lol