Help on Fine Tuning my 2003 400 ex

[Beep54]

2003 400ex,
Currently Running K&N Filter no air box lid
Stage 2 Dynojet
and full White Brothers E-Series w and w/o disks (testing)

Trying to stop backfiring and just make engine run somethere and hoping to eliminate Black in the exhaust a little

Looking for advice, tips, or specs on what to do to the motor

Engione runs great no misses or anything just me being picky :devil

Appreciate any and all feedback

[K_Fulk]

Throw away the dynojet, go buy a 155 main jet and a 40 pilot and turn the screw on the bottom of the carb a half turn to the left.;)

[Beep54]

wouldn't 155 be a little much for a 400 with no engine work

[K_Fulk]

It wasnt for mine but there all a lil diffrent. I kept the same jetting after i had motor work though. I think what effects it most is the air going in a out, with a open airbox and full pipe you should be ok with that jetting, if not get a 152 main too.

[Beep54]

hmm well i'll have to see what i come up with, im heading to kellner motorsports this week sometime im hoping, so i'll pick em up and give em a try