2003 ltz 400 popping and spitting at high speed

[hhaceesa]

anyone else have a prob with ltz 400 spitting and popping at high speed. i have a white bros. pipe dont know the jets runs ok but my friends 2006 has about 10 % more power.. at topend bike just doenst feel "right"

[John Noftsinger]

Did it get jetted when pipe went on ? if not buy jet kit so you get needle too.

[hhaceesa]

YES IT WAS JETTED WHEN EXHUAST WAS INSTALLED NOW IM GONNA DROP AND CLEAN CARB AND CHECK SETTING AND JETS AND IF ITS STILL NOT PERFECT IM GONNA SWITCH TO FMF WITH MEGA BOMB COMPLETE SYSTEM AND GET IT TUNED BY THE "SHOP"

[John Noftsinger]

There an air /fuel mixture screw under carb under a steel cap ,I thinks it in front of carb towards front of quad, pop cap off be careful and make sure screw driver is a small skinny one or it will crack housing trying to use regular one, turn screw out little by little might work for you they might not have adjusted the right amount, turn all in then out little by little mine 31/2 turn out you should be around same .hope it works for you unless it a clogged jet but just sounds like the air/fuelmixture screw needs adjustment or the jetting is wrong.