engine popping?

[Curmudgeon]

I've recently done maintenance on the motorcycle, including adjusting the valves and synchronizing the carbs.  When finished, I noticed a popping on the left Bank.  At first I thought it was a vacuum leak and checked all hoses and caps.  I still have the popping.  It seems to happen only at idle.  I'm looking for either reasons for the popping and where to look to correct it. While I was  synchronizing the carbs it seemed to be coming or was most pronounced while adjusting cylinder six.  I assume it's probably related to the carburetor, but where in the carburetor? Any suggestions?

[Ricky-D]

It would seem you have a loafing cylinder. That's the one which is popping.

Go back and refine the synchronization.

That should solve that popping at idle.

***

[Joe Hummer]

Hey John,

A few things could cause the popping.  If your carbs aren't sync'd or if your valves aren't adjusted properly, it will pop (no offense to your mechanical abilities).  Vacuum leaks is another.  A commonly overlooked one is the intake o-rings.  Lastly if your carb is running too lean, it will pop.  Lastly, if your air filter is dirty, it can cause the popping.  

Since you just performed the carb sync, I would look at the air filter.  

Joe

[fudgie]

Check your header bolts.

[Dave Weaver]

#6 has the hose that goes to the petcock.  Replace it if you think it may have a crack or hole.