jetting with stock setup

[drchoicey]

hey
i want my sons 400ex to run cooler not louder
has any one rejetted with the stock airbox and
exhaust.what size did you wind up using
for main and pilot?
thanx
the doctor

[GPracer2500]

Elevation? Typical riding temps? They'll both make a difference. I'd prolly just try one size up on the main and richen the fuel screw 1/2 a turn or so (and/or go one size up on the pilot jet). But again, that's just general advice--different engines in different places will respond best to different jetting specs.

Obtaining a range of jet sizes that allows you to experiment with different sizes is almost always a good idea. Plus that prepares you for future re-jetting as environmental conditions and mods dictate.

Good luck!