Jetting question.

[TRXNICK]

My brother-in-law just purchased a jet kit from FMF. It came with about ten differant jets. He wants to know witch jet will give him more mid to upper power. He owns an 04 400EX, it has a K&N filter and the baffle has been removed from the stock silencer. The shop he got it from told him to set it up for 3000' elevation. Any help would be great, thanks.

[bwamos]

The Jet kits usually come with instructions. You're probably gonna set it up as a Stage1.

[mojavedude]

any jet will give more mid to upper power. the main jet only kicks in at 3/4 throttle (correct me if im wrong) so as long as you get the jetting right, he will have more mid to upper power. start with 1 or 2 sizes first, then you just have to see what feels best. you can also do a plug check. change you jet then warm it up to normal opperating temps. then putt it under a load on the street where no one will get mad. just ride it in a kinda a high gear revving over 3/4 throttle, that way you will be using you main jet only. then hit the kill and pull the clutch. you shouldnt let the revs come down cause it might clean the plug. once you stop check the plugs color. theres plenty of picture on google of plug colors.

since your at a higher elevation, you wont have to jet as high as you would if you were at sea level. jet 1 size down for every 2000 ft of elevation you go up.

it might even out though because normally you would jet up for his mods and down for going up in elevation, i guess its all trial and error. good luck