happy new year!!!! i am sure its here somewhere could not find. 72 combat with mikuni was running good been sitting 6months. runs with chock on when choke is turned off starts popping missing etc. till it stops running if chock is put back on it runs fells like it starving for gas carb has a 250 main jet needle was set in middle slot i moved it to one slot above middle same thing happens i read on a post they used a 230 main dont know if that would help thanks for your help mike
mikuni help
- Thread starter preston
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I concur, when I get lazy (happens often) and don't drain the carbs on any of my bikes,
they all fail to run properly without first dissembling and thoroughly cleaning the carbs.
My XS650 gets cleaned twice a year, and since I have ignored my Combat due to the freezing weather,
it will need attention next time I try to start it. The Buell Blast will need it in the spring, this I know.
Learn to clean them and live with the fact you will need to once or twice a year.
Ethanol is bad, ummm kay!
they all fail to run properly without first dissembling and thoroughly cleaning the carbs.
My XS650 gets cleaned twice a year, and since I have ignored my Combat due to the freezing weather,
it will need attention next time I try to start it. The Buell Blast will need it in the spring, this I know.
Learn to clean them and live with the fact you will need to once or twice a year.
Ethanol is bad, ummm kay!
Something out of left field.
I had a similar problem, start and ran on choke but engine would stop if choke was off. The engine would only run if I held the revs high. If you have a single mikuni like me then check the two cap screws that hold the manifold on (the inside pair inside the manifold).
Why you ask, well one of mine came out and was found sitting ontop of the inlet valve.
The engine gave all the appearances of an engine running lean, and it was as the manifold now had a big hole to the outside where the screw was.
Anyway food for thought.
I had a similar problem, start and ran on choke but engine would stop if choke was off. The engine would only run if I held the revs high. If you have a single mikuni like me then check the two cap screws that hold the manifold on (the inside pair inside the manifold).
Why you ask, well one of mine came out and was found sitting ontop of the inlet valve.
The engine gave all the appearances of an engine running lean, and it was as the manifold now had a big hole to the outside where the screw was.
Anyway food for thought.
i THOROUGHLY cleaned the idle circuit and that did it THANKS
now i noticed blue smoke on decelerate out of right exaust hope the valve seal didnt come off agian iput the good ones on last time. what do you think about this small leak at rear of new base gasket forgot to torque thought i could losen all bolts remove coils head steady etc. slide everything up little sealer retourqe instead of pulling barrel etc mike
now i noticed blue smoke on decelerate out of right exaust hope the valve seal didnt come off agian iput the good ones on last time. what do you think about this small leak at rear of new base gasket forgot to torque thought i could losen all bolts remove coils head steady etc. slide everything up little sealer retourqe instead of pulling barrel etc mike
Your base gasket leak can be fixed like you mentioned. I had same issue and slid everything up just enough to put whole new gasket on. I cut the gasket only at the front stud down the middle of the stud hole. I didn't cut the entire gasket in half, just that one place. Then used a dab of heat sensitive sealer.
Tim_S
Tim_S
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- Nov 3, 2011
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Once you have a nice clean carb the best thing you can do for yourself is to treat the gas with "Sea Foam" gas treatment. This will keep the gas from going bad and keep the carb clean. It is the only one of the gas treatments that I have used that actually did what they said it would do. You can get it at most of the auto parts stores.
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