Motorcycle Repair: backfires via carbs or dies, yamaha 1100, sound changes

Question
My yamaha 1100 v star custom runs very strong 90% of
the time then somthing strange occures.
As I am ridding the engine sound changes it dosent
have the zip it did and at times always as I am just
abought to stop the engine will die and start back with no problem. I have drained the fuel tank and
carb bowles this seemed to help then it would start all over. Carb backfire also seems to often 2-3
times per days riding.
tx Dan  

Answer
Hi Dan,

Sorry for the delay in responding to your question.

With the information given, I suspect the gas in the carbs may have varnished a bit and is causing the problems. Otherwise, there may be condensation in the tank or other gas contamination.

Describe the appearance of the spark plugs. Was the MC stored or parked awhile? Any history of repairs or service?

Respectfully,
Mark Shively