I have a Pro-Circuit T-4 slip-on and a K&N with Dyno-jet kit. The quad has great power from bottom to top, but when I let off the throttle, it backfires. Could this be the air/gas mixture needs adjusted? TIA for any help....[img]i/expressions/face-icon-small-cool.gif[/img]

 

Your too lean on the idle circut. Either adjust your fuel screw or put in a bigger pilot jet. Or both.

 

lol mine was doing just this, a freaking header bolt broke off in a cylinder and i took it to the shop. Their working on it right now gona cost me the better part of 400 bucks to get it fixed. They have to take it apart and send it off to get lazer cut out [img]i/expressions/face-icon-small-sad.gif[/img] So make shure your pipes are all tight [img]i/expressions/face-icon-small-sad.gif[/img]