still weak fire one #2 cyl

[Black wing]

so far ive changed the plugs and played with a few different gaps, new plug boots and wire, changed the airbox and carb boots, new airfilter, cleaned the carbs, synced numerous times, set valve shims, changed the ignition coils, upgraded tci to ignitech tci.

 

im stumped, whats next an exorcism? any one else ever have just one cylinder that would not cooperate?

[Flyinfool]

Ever run a compression check to see if there may be a mechanical issue?

[Black wing]

yup ran one last night and got 92 one both left cylinders and 90 on both right cylinders

[Marcarl]

As it is running, squirt some carb cleaner, or WD40 into that cylinder, if it responds to that encouragement, I would say you have a carb issue. Too much fuel will cause a cylinder to miss-fire as well as too little fuel, it needs to be close to right.

[easternrider]

yup ran one last night and got 92 one both left cylinders and 90 on both right cylinders

any one else ever have just one cylinder that would not cooperate

?

 

I had my #2 cylinder that would not compress up over 80 psi. Kept pouring seafoam down the cylinder every few days, and running it a few days later. Also put some in the oil. Did a compression test the other day, and now have 150psi........go figure.

 

Just a guess, but maybe your valves are leaking by. Try an air test one cylinder at a time. Hook an air line to the compression fitting and screw it into the cylinder. If you start with #1, put it at TDC. If it is exhaust valves leaking, you will get air coming out the exhaust pipes. If it is the intake valves leaking, you will get air coming out of the breather box.

[Black wing]

its starting to seem like the idle circuit in that carb is plugged up ive cleaned the carbs but wil probably have them ultrasonically cleaned next week when i get back from Ontario, maybe it will clear up with the miles