GENE426 My Ride Posted December 16, 2004 I Have A 2004 Yz450 And Put A Powerbomb Fmf Header And A M4 Muffler It Look Just Like A Fmf Muffler And It Seem Like It Backfires (pops As I Decelerate) More Than Normal, Whats The Jetting Suppost To Be? Im At 700 Feet In San Antonio Tx And Know Squat About Jetting Share this post Link to post Share on other sites
GENE426 My Ride Posted December 16, 2004 Sorry 400 Feet I Ride In Floresville Tx Share this post Link to post Share on other sites
rucka356 Posted December 16, 2004 Mine did the same thing when i put a pc muffler on. Turn the fuel screw out a quarter turn. If it pops more, then turn it back in a half turn so that ur richening it by a quarter turn. You can probably fix this problem my adjusting that fuel adjustment screw!! Share this post Link to post Share on other sites
