Motorcycle Repair: EXHAUST BACKFIRE, suzuki marauder 800, air fuel mixture

Question
I BOUGHT A 2000 SUZUKI MARAUDER 800 THAT CAME WITH A VANCE & HINES EXHAUST.  THE PROBLEM IS THAT WHEN I SLOW DOWN IN TRAFFIC OR LET OFF THE THROTTLE IT BACKFIRES THROUGH THE EXHAUST.  THE EXHAUST HAS BAFFLES INSTALLED.  IS THERE JETTING PROBLEM OR SHOULD THERE BE A BALANCE TUBE BETWEEN THE TWO PIPES?  IT'S VERY EMBARASSING TO RIDE SUCH A NICE BIKE AND HAVE TO DEAL THIS BACKFIRING ALL OF THE TIME, ESPECIALLY WHEN I RIDE WITH FRIENDS.  THE BIKE HAS 4,000 MILES ON IT AND OTHERWISE RUNS GREAT.

Answer
Hi Charles,

The problem could be worn or defective air-cut off diaphragm valves on the sides of the carburetors. These diaphragms are used to reduce or eliminate deaceleration backfiring.

Another possible cause that comes to mind is a lean air-fuel mixture. Engines produce optimum power just lean and a result or indication is the backfiring you described. I target this when tuning roadrace machines. I agree, it is not a desired sound on a hot looking MC on the street.

I don't believe a cross-over tube on the exhaust would do anything for backfiring.

Describe the condition of the spark plugs.

Respectfully,
Mark Shively