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Discussion Starter #1
This does not only apply to the 450R, this is a question for all quads! Well, all vehicles that don't have fuel injection...

The higher you are in elevation, the larger the jet size you need, correct?
 

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I think its the other way around....Im not sure though...I think its the higher elevation the smaller Jets you want, because there's not as much oxygen, so you dont want as much fuel. or you would be running rich.
 

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Discussion Starter #3
That is exactly what I thought, but when I asked on another forum a while back they said that because of the air being thin, more was able to flow into the engine, causing a need for a larger jet...can anyone confirm either way?
 

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they are right on more air but the problem is there is more air but less oxygen. ...So although you are getting more overall air, less of that air is usable.
I think!
 

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here is a little something about jetting that i found crusing the net.

When an ATV leaves the factory line, its carburetor is jetted for use at or near sea level. If you’re going riding at 6,000 feet or higher above sea level, you may need to rejet to meet the changing air requirements — especially if yours is a two-stroke engine. In these mountain environments, the air is thinner. If you leave the stock jets in place, the carburetor will be sending too much fuel for the air at altitude, and you’ll get a rich fuel-air mix.

This will cause a bogging, sluggish power delivery. Smaller jets will better balance the mix. Air temperature differences can also require jetting changes. Colder air is more dense; like there is more of it in the same amount of space. That means there’ll be more of it in your carburetor venturi, so you’ll need more fuel through the jets to readjust the fuel/air mix. That doesn’t mean you automatically rejet just when the temp drops, "you rejet when you need to rejet," to paraphrase Penland.[/b]
 

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