400ex jetting at higher elevation

[garthedavidson]

I live in utah elevation is 4500ft having problems jetting my 400ex. after I thru on a slip-on pipe and a uni intake. do I change my clip possision and go up on main or what please help this jetting thing is driving me crazy. It seams everyone lives at sea level except me. the honda dealer here is clueless.

[JOEX]

Generally you'll need to go leaner for higher elevations, smaller jets. If you need to lean out the needle circuit you'll want to lower the needle by raising the clip.

[400exrider707]

So are you asking what to do if you're jetting for a higher elevation, or are you trying to jet for the pipe and filter at a higher elevation? It sounds like you put a pipe and filter on but are at a higher elevation. What elevation are you at? I'd do a 155 main, 40 pilot and drop the clip down one notch on the needle. Start with that and see how it runs.

[garthedavidson]

4500 ft Above sea level. and I had 142 jet on my 400ex before I put the pipe on and uni on and it ran flawless at that. the plug was perfect. usualy how many jet sizes and clip possisions do you go up when you do a pipe and intake?

[JOEX]

I bought my quad with a K&N, WB slip-on and a 150 main. Ran great from sea level to around 3000' or so. I'd guess a 148 is close for you but if you want to really dial it in get every jet from 142 through 155, maybe higher if you plan on riding at lower elevations. I don't know what sizes are available between 142 and 148.

[garthedavidson]

I put in a 150 and it cuts out on the top end is it running to lean?
I havent changed the clip posisions at all should I?

[JOEX]

Originally posted by garthedavidson
I put in a 150 and it cuts out on the top end is it running to lean?
I havent changed the clip posisions at all should I?
Probably too rich on the main jet which controls most of the top end. I'd try dropping it down a size or two before changing the needle setting. Remember to only change one jet circuit at a time.