how does elevation change your jetting?

[Out_Sider]

i've always wondered how elevation exactly changes your jetting, like does it get richer the higher you get, or opposite? thanks


darrell

[NacsMXer]

As altitude increases, oxygen density in the air decreases. So an increase in altitude with the same jetting will cause the quad to run richer than normal (as the oxygen is less dense in the air/fuel mixture). A decrease in altitude is simply the opposite :)

[cals400ex]

in easy terms, at higher atlitude, jet smaller. at low levels, jet larger.

[Out_Sider]

well i have a race this saturday in a higher elevated area (foothills of the mountains) and right now im a tad bit lean at my elevation, so do you think at the track up there my jetting will be just about right? (i have the edelbrock so adjustments arent difficult just time consuming)

[cals400ex]

how much higher elevation are you going?

[RiderTRX400ex]

**** im at just under 500ft above sea level and im lean still at a DJ 165 main...

[Out_Sider]

its a pretty good difference, im around 200ft and the place is like 800-1200

[cals400ex]

i would bet it would change 1 or 2 mainjet sizes. that is kind of a guess so i am not 100% sure. i would just try it out and see how it runs

[cals400ex]

Originally posted by RiderTRX400ex
**** im at just under 500ft above sea level and im lean still at a DJ 165 main...



how can you prove you lean?

[thomps6s]

Originally posted by Out_Sider
its a pretty good difference, im around 200ft and the place is like 800-1200

I went from around 1800 feet in Minnesota to close to 6000 feet in Idaho and I never rejetted my ex with a slip on pipe and outerwears. It ran mint.