Jetting help 07 Kx250f

[04-250f]

Ok i had the jetting all perfect for race gas and all that. I just put a Full Yoshimura exhaust on it and now it backfires on Decelleration. Would it be my pilot jet? and if so, should i go bigger or smaller.

[Pr1malR8gw]

What's you elevation, and current jetting. Also what fuel are you currently using..

If you're at a 42 pilot and less then three turns on the fuel screw. You probably only need to turn out your fuel screw till it goes away or if you hit 3 turns go to a 45 pilot. and adjust the fuel screw from there.

On a side note, you may need to go one clip on the needle richer..

[Racer24]

i would move to a 42 also...but u might be able to solve the popping by thurning the fuel screw out...

[DGRAHAM]

no no no no it's cause you put that yosh full system on there,....junk.....jk:), definately jetting, everything previously mentioned is exactly right!!!! just wondering, why the yosh, why not somethin else, just curious not trying to be a dic, cause I really like the way the look and sound, but if I was riding a quad the yosh would be the way to go, but on a bike, I was very disappointed in the performance, but who knows could of just been THAT bike.

[Pr1malR8gw]

Arn't you nice Dgraham about his choice in pipes... Hahaha

[04-250f]

Haha it's all good. I got the yosh cause it was brand new still in package for 300 and its the full pro series 700 dollar system never used. Not sure on the elevation but i have a 42 pilot jet in it already, but i don't think im three turns out on the screw yet so i will try that an see.?