Say I remove my airbox lid and mess with my stock exhaust . Where do I find an assortment of jets and what am I suppose to be looking for ?
What brand and or model type of carb. does my 07' 400 ex. have on it ?
Thanks,
D.

 

Hondas use keihin carbs. The main jets are the hex head type, and the pilot jets are 21 or 26 series. http://www.jetsrus.com/main_page.htm, go here, and look up the jets for a 400ex, and there will be pics, and jets for sale.

 

About what size main jet am I going to have to go to ? I live in Iowa so this is the altitude .
Thanks,
D.

 

If you remove the lid , and take out the baffle...id start at plus 4, a #158, and a #42 pilot jet, and go from there