***exhaust popping/backfiring question***

[nowukno]

I have a 05 400ex with pro circuit full system , stage 2 dyno jet kit , srp rev box and a k&n filter with outerwear and ehs racing air box lid. My problem is when im going down a hill or let off the throttle but dont pull in the clutch the exhaust will make a popping sound , its not a big problem but its very annoying , do you have any suggetions , my buddy said to replace the stock pilot jet with a 40 or 42 pilot jet , what do you guys think i should do to fix the problem?

[2004exrider]

get the 42 pilot, also check your spark plug and make sure its not lean, if so go up in main jets until you get the right one. (even a perfectly jetted quad will make pooping noises when letting off throttle if you put on an afer market exhaust, some one correct me if im wrong though.

[2004exrider]

...meant popping:rolleyes:

[muddy400EX]

haha, you said pooping:o :p :D

[Woodsrider]

Did you install new copper gaskets in the head when you put that system on?

[nowukno]

no i diddnt since i only rode on the stock system for about 2 weeks (6 or 7 hours)

[Woodsrider]

More than likely, thats your problem. Those gaskets only crush once. Buy new copper gaskets and try again. I bet you'll find your problem solved;) Been there done that, Thanks Rico:D