I'd love some jetting advice!

[DuwBra]

I have a completely stock 400 as far as the engine goes, I have an open lid airbox and a kandn filter with outerwears, and i just purchased a hmf slip on exhaust and white bro rev box. Im looking for suggestions on jetting, i know jetting is really trial and error kind of, but I am just looking for a starting point.

[DuwBra]

bump

[hornetgod13]

40K pilot 155K main should be a good starting point. Plug check and go up or down from there.

[01 400EXer]

I have a 2001 with 6 holes in the airbox lid and and HMF pipe. My jetting is a 42 pilot jet and a 158 main for the summer and a 160 or 162 for the winter. I probably do not have to change between seasaons but I do. Mine runs great. I would get an assortment of jets 155 thru 165 main jets and a 40 and 42 pilot jet to play around with.

[DuwBra]

thanks guys, do i need to do anything with the needle jet or leave it be?

[01 400EXer]

I left mine alone.

[wildyellow400]

I took baffle out of exhaust cut hole in airbox lid and am running a 155 main 42 pilot works perfect