2002 400EX
XR's Only 430cc Kit, 10.5:1
HRC Copy Cam
5-angle valve grind
Pro Circuit T-4 slip-on
Stock header with welds ground down
airbox lid removed
stock ignition
stock carb
Location: Central Indiana

Any suggestions on where to start with jetting? Before the 430 kit, cam, valve job and header mods, I was running stock jetting (148 main / 38 pilot). Any help would be appreciated.

 

I would think somewhere about 160-165 for the main. Go to a 40 pilot and raise the needle one clip. That is drop the clip one spot. That seems to be a good starting point for the modded 400's.