Motorcycle Repair: Backfire through exhaust, straight pipes, exhaust pipes

Question
I just changed from stock exhaust pipes to 2" straight pipes with AR or tork cones on a 107 C.I. S&S engine on my Big Dog chopper. The pipes are Santee Big Bear Venom. The Bike seems to run well after minor carb adjustment to improve idle. It would die at stoplight. The problem is backfiring through the exhaust when decellerating while riding. The higher the rpm, the more backfire. I certainly do appreciate this service you provide.  

Answer
Check for a intake or exhaust leak. You can check the intake by starting the motor and spray a little carb cleaner around the intake manifold. If the RPM's go up then you have a leak. On the exhaust, check where the exhaust pipes connect to the heads. You can carefully put your hand around them and see if you feel a leak or use a match to see if it gets blown out.
Good luck and happy riding
Mike