High altitude jetting [Archive]

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Nate408

07-19-2005, 02:00 PM

Going to silverton, Colorado in 4 weeks need to know a base to start with jetting. 400ex, 10.5:1 je with c&d thin cometic gaskets, stage 2 cam, hmf slip, k&n no lid. Right now in oklahoma running 168main, needle 1 position richer than stock. Buddy has 400ex also with fmf powercore4 slipon and k&n with lid on. If any body rides in colorado could help would much appreciate it. Ihave jets from 168 down to 148. thanks,
Nate408

Nate408

07-20-2005, 10:37 AM

anybody out there?

BLAZZIN

07-20-2005, 02:49 PM

I run a 148 main jet in a stock 400ex in Fort collins, Colorado. And it is around 4900 ft

plkmonster2

07-21-2005, 01:21 AM

What is the elvation? I'm thinking 5000+? Your jetting seems rich for your bike, but everyone is different. I would try both a 165 and a 162 main, and try to move the clip up to the middle slot, and see how it runs.

BLAZZIN

07-21-2005, 09:44 AM

I WAS JUST IN SOUTH DAKOTA AND I HAD TO RUN A 160 MAIN JET . RUNNING A 148 HERE IN COLORADO WORKS GREAT AND I HAVE GREAT THROTTLE RESPONSE.

Nate408

07-21-2005, 10:48 AM

Thanks alot guys, i will be taking jets & plugs but ill probably move the needle & adjust the pilot screw before we go. Just helps to see what others might be running since ive never ran the bike a that kind of elevation. or outside oklahoma for that matter. Does the elevation reduce an engines octane requirement? Seems i have heard something about this before.
Thanks,
Nate408