high elevation differant jet?

[cabby]

I noticed in the owners manual that it said at elavations above 3000 ft a differant jet could make a differance in performance. I live in the black hills of SD and the elevation is anywhere from 3200 up to 5700. Does anyone think I would gain anything by using a differant jet? I own a brand new 04 ex I have noticed the performance is kind of choppy from time to time. Sometimes driving it seems like its lacking or maybe getting to much fuel, if I give more throttle it gets rid of the problem. I dont think its my shifting......

[Ex'r Marlin]

Well, first of all, congradulations on having a "Honda 400ex", and for being engaged!:)

I believe in your situation with a stock 400ex at the elevation you are at, that leaving the stock jet in there and going with an aftermarket air filter, like K&N, will allow more air in, which will lean the mixture a little, and ultimately, give you better performance.:D

Best Wishes!

[cabby]

thanks for the input ex'r ill try that and let you know how it goes..

[cals400ex]

the 400ex stock comes with a keihin 148 mainjet. in some situations, it comes with a keihin 142 mainjet. this is if you live in high elevation areas. so i would guess you have the 148 in but no one knows unless you check. so, at higher elevation levels you will need to jet smaller.