crixal
05-15-2008, 06:08 PM
i know this has been a subject thousands of times on here, but i'm gonna ask it again. i have a 2007 400ex. i put a full system ct racing exhaust and k&n filter. i put a 172 keihin main jet. that is what the company i bought it f/ said to install. since the install the quad has been harder to start and sputters when i ride it sometimes. the sputtering doesn't happen all the time, just mostly 1/2 to full throttle. i have tried air box lid on and off. it seems to be worse w/ the lid on. it absolutely won't start w/ no choke no matter what the weather is. it was extremely hard to start in the winter when it was stock also. it starts fine w/ the choke on. this time last year stock it won't fire right up. i haven't got a chance to look at the spark plug, but i think it's running too rich. i could be wrong. any help would be appreciated. thanks.