440ex needle adjustment questions

[sportraxkid]

I have a 400ex with 11.1 compression wiseco 440 piston, stage 2 hotcam, Uni filter with no airbox lid, fmf powerbomb headpipe and pro circuit t4 silencer, and a white bros cdi. I have a 42 mainjet and a 168 pilot and the elevation is about 5000. I have never adjusted my needle jet and was wondering if I should or if it would make a diff. will a 440 run better with the plug the light brown color or black. Cause my local dealer said they run better rich. also I just put the powerbomb header on it today could that affect the jetting much? and no I dont have a ported head

[nosliw]

yea richening up the needle should make a noticeable improvement.

and the thing is going to run better at light brown than it is at black. dealer says it runs better rich? in my understanding it doesnt matter what kind of gas engine you have, 14.7:1 burns better than <14:1.

you may have to rejet or may not. do a plug chop and see.

[mojoe2878]

yeah it will run better when the plug is brown and not black from being rich. maybe the dealer meant its better to run it rich than lean, but idk. i never ask the dealership anything because you usually get screwed up answers.
im suprised you are running a 168 main and its not lean, i have pretty much the same set up but with a web cam and i had to run a 175 main with the needle clip moved down a notch to get it right.
if you want to try to move the needle and see if it helps out some then move the clip down 1 notch at a time and see which position is best for you, just remember that you want notice a difference in the needle position until you get past the 1/4 to 1/2 throttle range, so you will need to open it up a bit when you ride to be able to tell if it helped or not.
after you add the header you may need to up to a 170 or so to compensate for it.