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View Full Version : ***exhaust popping/backfiring question***



nowukno
04-30-2005, 05:26 PM
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?

enduro400rider
04-30-2005, 05:40 PM
yeah sounds like your running lean richen it up a bit. my 400 was doin that i just richened it up and it hasnt don it since

JR3
04-30-2005, 05:50 PM
Your jetting is probably off.

muddy400EX
04-30-2005, 07:27 PM
mine pops a little bit after giving it gas and not pulling the clutch but its not like a loud pop, its like, buh buh buh buh. lol. pretty much every piped quad ive ever seen pops a little bit tho:)

cals400ex
05-01-2005, 02:16 AM
yep you need a larger pilot jet. i would get a 42. on the 05's i do think the fuel screw on the carb is different than the previous years. so i am not sure how your supposed to adjust that thing because i haven't seen an 05 yet.

nowukno
05-01-2005, 04:46 PM
any more suggestions?

QuadJunkies
05-02-2005, 09:07 AM
my quad does that and its not lean.. It a little fat right now actually, but it sounds good ,no popping while riding just a slight blubber from being on the fat side . I also have a bigger Pilot on mine, I am running the 440r Carb on my EX though.