Carb problem?

Terry · Post by **Terry** » Mon Jul 20, 2009 3:36 pm

Its hardly a problem for me but I've noticed that on my 79 at a steady throttle the motor pops thru the exhaust occasionally. It also pops under decelleration a bit. When I go wide open it runs just fine. At idle say up to 3,000 revs, holding the throttle steday I hear a staccato sound thru the exhaust. Out of synch maybe? Need cleaning? If the valves were out of adjustment could they be the cause?

alimey4u2 · Post by **alimey4u2** » Mon Jul 20, 2009 5:48 pm

Terry as well you know I'm almost hopeless on Keihins but... There is an air shutoff valve whos sole purpose is to stop backfiring on overrun... Check the diaphragm for holes/leaks...
Other than that, an air leak either on your exhaust or inlet or both.

I would wait however for someone more knowledgeable on Keihins...

steve murdoch icoa #5322 · Mon Jul 20, 2009 8:07 pm

I hate to tell you this Terry but i agree with Larry that an air leak makes more sense than valves or dirty carbs.
I am a carb numbskull.
I solved a similar problem on my '79. I re-used the exhaust gaskets one too many times i guess. New copper rings and the popping on decceleration all but disappeared.