Motorcycle Repair: 74 360CB Honda backfire, twin carbs, air screw

Question
I am restoring a '74 Honda 360CB that has been sitting since 1982.  I have cleaned the tank, replaced the fuel lines, cleaned the carb and jets, etc.  The motorcycle will start and run, but it backfires when I first turn the throttle from idle.  This motorcycle has twin carbs.  What is a common reason for backfiring.  Also, can you tell me what the correct factory adjustment for the fuel and air screw on the carbs.  The bike doesn't seem to want to idle very well.  One more thing, the left exhaust pipe has holes in it.  Could this cause the backfire?

Answer
Hi Doug,

Backfiring may be fuel related, but I suspect it is likely a result of an ignition problem. Check breaker point gap and ignition timing. Check carburetor synchronization. The pipe must be repaired for proper operation.

I don't have a service manual for the CB350/360, and I cannot remember the specs. I use 2 turns out as a base setting for most carb work.

If you want my carb tuning files, send me an email. My email addy is: mshively1@woh.rr.com

Respectfully,
Mark Shively