well having the engine run out of power at the high rpm's is a classic symptom of running lean....but what is a keaon carb? Are you running some aftermarket carb or is it stock? And its my understanding that after you remove the choke it doesnt matter what you do with the screw as it would be adjusting the choke that has been removed.

 

its a keihin carb and it is stock on the 2001 400ex. According to the plug i am nice and brown at this setting, with all the other adjustments i listed earlyer i was rich. I have yet to be able to make it lean according to the plug.

 

well from what I've heard reading plugs is kindof an art...not a science. But I just go by what feels right. Mine will pull until right almost before it hits the rev limited. It stops making power and then bam i hit it...not that I rap it out that far often, I just noticed it in the dunes where I was racing buddies and messing around. I wonder if you should try something like this... Thunder Products Dial-A-Jet | Rocky Mountain ATV/MC it would take the guesswork out of this for you but it isnt free.