1997 Road King, stock engine, 2-into-1 DG exhaust, HD airbox kit, rejetted original carb, 24,000 miles on bike. Acceleration is good and recent fuel economy check on round trip to Rolling Thunder was 47+ mpg. While riding bike, exhaust backfires/pops when letting off of the throttle in any gear, very annoying not just to me but to other riders. Idle is ok, at about 900-1000. Tried adjusting the enrichener, but would only raise the idle and would not stop the backfiring/popping.