need to figure out my jets

[atvdreamer69]

i just put a modquad air intake with a k&n filter and pre filter, stock exhaust exept i got an aftermarket tip on it without baffle running a spark arrestor screen. quad runs like poop now. runs but when i give it gas it sputters and dies. ive got an fmf power up jet kit on the way but was wondering how hard it is to do the main jet and pilot jet. ive got an 08 400ex, thanks

[3400ben]

http://www.atvriders.com/articles/pilotjet.html This should help.

[atvdreamer69]

thanks i was afraid of that. i didnt want to take the whole quad apart but i guess ill have to. im gonna wait till i get the new exhaust on it before it jet it. i just ordered a lexx mxe exhaust and mid pipe so my quads about done for now.