backfire

[$$$moneyex]

i heard some guy say in another post that if your pipe backfires when you let off the gas you should rejett. mine does this. how much do you think i should rejett. i have a 250ex with a t4 does like 4 up on the main sound good? its a 96 stock. i think

[400exdad]

You probably need to rejet the pilot, not the main. You may be able to get away with opening up the air screw... or is it a fuel screw. Anyway, out should be richer. When you let off the gas and it backfires, its in the idle circuit and is lean. My 300 did it all the time, even with the stock pipe. It still has the stock pipe and I finally put a bigger pilot in it to make it start easier. It also fixed my backfire. Good Luck. If you c/o the pilot, probably just 1 or 2 steps should do it.

if it backfires when u let off the gas, are u at a real high rpm when it does it, or does it do it all rpm's, if its only at high rpm's, then its jus because u r runnin a low octane gas, wut octane r u running

[$$$moneyex]

probly the cheapest gas. it does it at high rpms, wheni keep it at a low rpm for a while, and when i go to do a wheelie and pin it real quik.

[kxrider]

my 250ex, does the same thing at high rpms, and have wb e-series, and it has been re jeted, stage 1 dyno jets, main, and piolet

wut i would do is run 92 octane and put in some octane boost so it would b running around 99 octane, thats what i would do b4 messing with the jetting and air screws(its 2 complicated)if it still is popping, then u might wanna consider changein your mixtures, like that guy said in an earlier post

[ryanh250ex]

i have a '02 250ex with PC T-4 Complete Exhaust (re-jetted too). i run 86-87 octane gas (regular) and my 250 makes a similiar noise at high rpms. i think on my next tank of gas i'll try going to higher octane. also, when i'm at a very slow speed and then i pin the throttle it seems to have a slight low-rpm sputter. i think that if i go up 1 on the main jet, this would cure it. does that sound right? i'm due to go back to get another basic service done ( i have 27 hours on the bike currently, i'll go in at 30 because i go in for a service once every 15 hours), and since the same guy who does my service installed my pipe and jets, i'll just ask him if he can go richer on the main. let me know if i could be wrong about this.

sry, like i said, im not a jeting expert

[RED121572]

Hey bud, listen to the first reply. Youve got a lean pilot jet.

[Buzzsaw]

check for exhuast leaks

[$$$moneyex]

theres no air leaks i checked and i screwed with the air screw and no difference im going to try a new pilot jet. just gotta get to my honda dealer somtime. id try a higher octane gas but my dad buys the gas and i cant afford to buy expencive gas right now untill i get a job.

[ryanh250ex]

Originally posted by RED121572
Hey bud, listen to the first reply. Youve got a lean pilot jet.

are you talking to me?

[OutlawEX]

Mine was back fireing a while back so i just dropped the main and it fixed it right up...