400ex Jetting with aluminum airbox

[python952]

My friend has a 400ex. He just got a UM aluminum air box and a K&N filter and air scoops. He needs to know what jet hes gonna need. Hes also running a white Brothers slipon.

[2001300exguy]

i have a aluminum airbox, and a full pipe. but i also got a 406, hot cam stg2 , high comp piston, and a port and polish and im running a 162 mainwith 3 1/2 turns out on the pilot screw
i htought that seemed a little low but the plug is a gray/ brown so its got to be close

[RiderTRX400ex]

158 -160 sounds like a good place to start, tell him to buy a few..

[zephead400ex]

I would recommend starting with a 42 pilot and a 155 main. That's a good start, but also run a plug check to see where you at.