Motorcycle Repair: ? about backfire from Kawasaki 1500 Vulcan, air fuel mixture, market pipes

Question
ok...the 1998 Kaw. 1500 Vulcan bought used,has a problem with backfire when useing the throttle. This happens both when cold and after warm at high speeds or slower speeds. The previous owner had Vance and Hinds after market pipes installed and said that at one time it did the same and it was with the seal at the exhast and the pipe bolts needed to be tightened. this was done on both exhast to no avail. Ive been told that it may be with the A.I.S. system and it may need to be removed. the pervious owner did have the carb re-jetted. do you think a new carb is in order or may it something in the gas or air flow system...HELP...  

Answer
Thanks, Tony.

The carbs may need tuning to get the correct air-fuel mixture. Popping of the exhaust can be a lean condition. (I target my race tuning for this as it pruduces very good power here.)

Does the backfiring occur on acceleration or deacceleration?

Is the air box and filter stock or modified?

What throttle opening position does the backfiring seem to occur? (i.e. 1/4 throttle) We use throttle opening positions to tune carburetors. RPM range can be helpful.

The carbs won't need replaced. They rarely wear-out and they are very expensive, more than top line race carbs.

New email address: "mshively1@woh.rr.com"
Respectfully,
Mark Shively