Little rich

[ohsobad_chevy]

I have a 2004 400EX, stock keihin carb, I am running a HMF full system exhaust, a UNI air filter (with the lid ON) I am currently at a 152 main and a 42 pilot jet and my needle clip is on the 2nd position from the bottom. I have the fuel mixture screw all the way in and 2.5 turns back out as well...I pulled the plug this last weekend and it was black and a little wet. I need to make it leaner, but i dont know how much. I dont want to run too lean, causing damages, but i definately need to lean it up some. Would I need to adjust the fuel mixture screw, or would I have to change the main jet. My next question is, how can I be absolutely shure that the Air/Fuel mixture is EXACTLY correct, Is there a tool that i can use to tell me?

I know its a lot to read, but all help is appriciated.

Thanks,

[2004exrider]

:confused: Jetting sounds about right? Try running it at 3/4 to Full Throttle and see if it bogs or sputters. If so then your main jet is to rich, try taking your airbox lid off and see if that helps.

Jimmy