jetting question when changing elevation

[bluebob71]

i just bought a bike from colorado and im in michigan would i have to go up in jet  size or down?

[Zino]

Try it as is first .
Stock bikes can handle quite a range of elevations.
Stock zumas run a 80
When you up displacement and peak rpm ranges you need to upjet
You will be on the rich side and might need to go down 1 jet size or just a small turn on the mixture screw .

[bluebob71]

Sept 7, 2020 18:53:05 GMT -5 Zino said:

Try it as is first .
Stock bikes can handle quite a range of elevations.
Stock zumas run a 80
When you up displacement and peak rpm ranges you need to upjet
You will be on the rich side and might need to go down 1 jet size or just a small turn on the mixture screw .

hmm any bike ive ever bought with even a lil change in elevation has messed with them.. guess i shoulda stated this but i asked because i noticed its a lil slower to take off then my other sym 200 but it wasnt the jet the carb was just setup shitty got it fixed. guy had the air mixture screw like wide open. i travel to new mexico a lot and have to have jets on hand for my trip but i kno colorados elevation is number 1 or 2 in the us so figured it be more then just that screw.

just noticed u said zumas, only bike ive never had to fiddle with in my travels was a zuma 2 strokes are a lil better when doing big changes like that

[snaker]

High elevations mean less oxygen in the air so a sea level mix will be too rich.
Bringing that high elevation mix down towards sea level will make a too lean condition.

I've bought snowmobiles from Rocky mountain rental outfits and brought them to 8-900 ft elevations. It was critical to rejet the two strokers richer to avoid damage.

Had to resize the cvt fly weights and sometimes the gearing also because the lower elevations make more hp.