Motorcycle Repair: 82 Virago 750 backfiring upon decelaration, air filter element, air leaks

Question
 I have a '82 Yamaha Virago which runs good going down the road, idles okay but when it comes to letting off the throttle it backfires through the exhaust. Occasionally it backfires when getting on the throttle, but more letting off. It is very inconsistent and of course does it at higher rpm's but at any rpm. Any help would be much appreciated!

Answer
Hi Gary...

Hmmm. a backfiring Virago... hard to say for sure without seeing the bike, but here are the usual suspects:

1) An air leak between one of the carbs and the engine.
2) A leak or hole in the exhaust system.
3) A problem with the air filter element.
4) The carbs are dirty or out of sync.

I use carb spray cleaner to check for air leaks at the boots. I spray alittle at the boots and listen if the engine idle changes. Hard to say which area to be suspect of, but I'm betting that one of the above four things is causing your problem. Also... pull the spark plugs and look at them. In a proper running bike, the plugs will look the same. If one of them looks normal but the other doesn't, then that can tell you which carb is the culprit. Hope this helps Gary!!

Jack