What size is a stock 400ex main jet

[yellow400]

Im' getting a big gun race slip on, and the guy at big gun told me to move the Main jet up one size, so what would that be?? and where can i get it?

thanks

[eldoexrider01]

im runnin dynojet jets and ive heard they are different in #'s than reg. jets. maybe someone could veryfy it for me. but if ya get dynojet for a 400ex 146 w/airbox lid 170 w/o

[400exRacerX]

Well the stock 400ex main jet is a 148.