jetting question

[rider250ex]

hey my friend has a 300ex with fmf full exhasut (powercore4) and a k&n and was wondering wat u think would be the best jetting for it

[cals400ex]

jetting depends on many things such as temp, elevation, humidity, mods, etc. its tough to tell but i would go up a couple sizes on the mainjet for sure. if your running an open airbox lid, you will need to jet larger. i think the stock jet is around a 122 in a 300ex, but i am not positive. it that is right, you may be able to try a 132 or so.

[rider250ex]

its running airbox lid. the exhaust and airfilter its like 20 degrees out and we are below 1500 feet

[cals400ex]

i am not positive the stock main jet size, but like i said, i woudl think that a 132 would be plenty big. try using the search button. i know i have read posts about jetting specs on a 300ex.