I put roadhouse slipons on my 2008 Roadstar and of course it is popping on the "totally" off position of the throttle, I am going to remove the AIS this Monday. I hear alot of bikers both on this forum and especially on the Harley forum I belong to( I own a Harley XL1200N Nightster)about exhaust leaks causing backfiring in the tail pipe( or muffler) as a result of lean mixture. Being 63 years old and riding bikes on and off for about forty years Ive seen and done alot of fooling around with motorcycles. Please don't take my questions wrong they are not ment to confuse or make argument, just to find out if some statements have been proven or are just being passed as truth. OK here we go. In the carb days, before government regulations, backfiring through the exhaust was generally caused by fuel sucked through the carb jets V.I.A the vacume caused by the pistons and probebly some air being pulled through the exhaust for the same reason, and when the intake valve opened( remember the throttle is closed, this is fuel getting past the not so totally sealed carb) the plug is still going to fire and you get a pop in the exhaust. This was not easy to correct. This used to happen on brand new just tuned bikes, especially when they had straight pipes. Now fast forward to the relatively new EFI systems which are not supposed to let any fuel through unless signaled by ECU. Soooo how can a condition exist on decel that would cause decel popping unless there is unburned fuel in the cylinders to combine with the air being leaked in. Is this not the reason for the AIS system? to burn residual fuel. The H.D doesn't have an AIS system so I am confused as to how a lean condition caused by the EFI could possibly be leaving residual fuel to be fired by combination with air leaking in through exhaust connections.