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,

[zeppelin]

taking the lair box lid off would lean it out some, if you dont want to take the lid off, then you could raise your needle

[KY Woods Rider]

Put the needle back into the middle clip position. I run mine in the #4 position (from top) during the winter, but it's too rich for temps around or above 50 F. You may also want to try going in a half turn on the pilot screw (AKA air/fuel screw).

[ohsobad_chevy]

I dont want to run it with the airbox lid off, I ride through too much mud and water. I am a crosscountry rider mostly...
I dont think that the tiny bit of difference in throttle response is worth sucking water in my engine.

[zeppelin]

i was just saying to try it out like in your driveway to see if it helped, and if it did then you would know if you were going in the right direction. really if you want to fix it right you need to change your jets

[ohsobad_chevy]

OK man, I got ya. I'll give it a shot. Thanks for the input fellas. Keep it comin'

[400exstud]

Are you running with the quiet core in. If so that does affect the jetting quiet a bit.

I also have the HMF full, K&N, quiet core in, and airbox lid on. Currently I have a 155K in with the needle in the 3rd (stock) position. With this my midrange is lean but not overly bad. This is because if there was a place between the 2nd from the bottom and 3rd from the bottom position, that is were my needle would have to be. I just couldn't take going through all of the plugs that it was eating. You may need to adjust your needle, too. Who knows.

Your main jet does look very good. Unlike most people on here you went lean enough for a pipe. I have seen people as rich as a 195 with just a pipe.:p

Hope this helps

[ohsobad_chevy]

No, I do not have a quiet core in. Ill try to step down to a 148 main and keep the 42 pilot. See what that does....

[400exstud]

let me know the result.