My new to me 03 DL1000 with 35,000 miles is backfiring under deceleration. It sounds as if its coming out of the exhaust and not the airbox. It idles fine and runs strong and has no skip or miss anywhere up thru the rev range. It has a PC III with unknown to me map, and stock exhaust. Im new to the world of the Vee and it almost sounds as if it may have an exhaust leak but im not sure.