Yet another jetting question for the 400

[SuperEX]

I need recomendations please, I have an 02 400ex with an E-series slip-on, K&N with outerwear in an open airbox(without lid).
when you let off it kinda pops a little. What jetting should I run? or should I leave it stock and just move the needle? My elevation is about 1000ft above sea level

I hate to ask this, but I'm really just not sure what to run.

[crashinmatt]

i would say try a 155 to 160 mainjet, and turn the screw out 2 1/2 turns from all the way in. that should about get u.

[Sparks425Ex]

I would think that a 155-158 would be fine for the MJ and bump up the PJ up to a 40 or a 42.


I had a slip on, a K and N filter and a Drilled air box and I was running a 158mj and a 40pj.


It was working for me. If it pops when ya let off the throttle then it is to lean.

[AtvMxRider]

SuperEx we run just about the same set up and I run a 160 main and a 42 pilot. I haven't touched my airscrew and it seems to do great.

[jb400exxx]

i have a T-4 and i run i dyno-jet stage 2 165MJ, and a 42 pilot, with the air screw out 2 1/2, and the stock needle in the stock setting.

[Team Outlaw #34]

i have a t-4 and with a k&n and i run a 42 pilot and a 158 main jet....

[SuperEX]

Thanks guys, this helps a lot!

[Wheelie]

Take a look at my sig, the setup works great!!

[JOEX]

Raise the needle one notch too. (lower the clip)

Joe