Topic: Running on 3 cylinders

[SkiLLzCb650c]

I have been messing with my 81 cb650c with CV carbs for about a week now. Its been running on all 4 until yesterday. I was riding around the neighbor hood and it started missing. I was messing with the e*haust pipes today because I had a loud tapping noise and thought I had a leak. I already got new gaskets on them.

Got it all put back together fired right up as always. All of a sudden #4 stopped and the tapping stopped.

I have spark at the plug when pulled out and grounded. Took off the bowl....gas looked a little dirty and black.....pulled the main jet and its clean. Gas is getting to the bowl.

Why is it tapping when that cylinder is working right and what should I do from here to get it working???

I havent done a carb sync but I have adjusted the idle screws. The accelerator pump has never been hooked up on this bike but I think I should probably put it back on. PO took it off and threw it in with my other parts.

Sorry bout the long post and thanks in advance for the help!

[SkiLLzCb650c]

I have gas to the cylinder now and am running on 4 but still when #4 is good it is ticking.....when I pull the wire off the plug the ticking stops

[jevfro]

that tapping sounds like an exhaust gasket, check them again   

[SkiLLzCb650c]

Is there a sequence to put the e*haust on? I have a 4-1. Would the gasket still cause the ticking if the cylinder wasnt firing? When I take the plug wire off the ticking stops

[SkiLLzCb650c]

bump

[jevfro]

I'm guessing that when there is no fire in the cylinder it  is not "ticking" because there is no explosion to cause an exhaust leak and the resulting pop,tap,ticking noises.

As far as exhaust assembly I think you just kinda bolt them up? The new gaskets can leak if they distort when compressed.  If they look like they're set evenly then perhaps it's something else.

[SkiLLzCb650c]

Thanks for the help. I adjusted my valves and took the pipe off #4 and doubled up a few old asbestos gaskets. Ticking stopped. It was definately coming from the pipe. I cupped it in my hand while running and it got louder. I tried just 1 gasket a few times but I guess this one needed 2.

Do these carbs get synced? Its running great from all my work but the carbs still need fine tuning. I will have my manual tomorrow. I cant give it full throttle without it sputtering. I set the air screws 1.5 turns out and hooked up the accelerator pump and its working good.

[Ibsen]

Did you make sure you removed the old exhaust gaskets? Sometimes it is difficult to see if they are in there because of the sootin the exhost port.
And the carbs can, and should be synchronized from time to time. But you should adjust the cam chain and the valves and check that the air filter is clean before synching the carbs.