Another jetting question....sorry lol

[yellow_sportrax]

I'm confused now. I'm trying to get my 400 running right but its not happening. All i have done right now is a Pro Design Pro Flow kit with no airbox lid. I have tried a 150, 152. and 155 main jet and it still runs like crap. Can someone please help me out with this. I've got a race sunday and I need to be on point. Thanks

[cals400ex]

what do you mean "it runs like crap?" is it slow? is it missing? does it studder? whats wrong with it????????

[prepracing]

what color was the spark plug ? if your running no air box lid you will need some where between a 160 and 168 depending on the weather where your at

[2004exrider]

http://www.atvriders.com/images/articles/sparkplug/sparkcolors.jpg

[yellow_sportrax]

Sorry should have been more specific, it keeps cutting out and you can sit there at idle and hit the throttle wide open, and it will just die like its not getting enough fuel. My elevation is 1000 above sea level. Thanks

[cals400ex]

i would start with the keihin 152 mainjet. you need to make sure the bike is 100% warm before you come to conclusions on the jetting.