Elevation ? too lean or to rich?

Ok I bought my bike from CA, witch the city is 60 ft above sea level..Im in iowa witch is 925ft. So will this make it leaner or richer? I think it will be leaner. but wanted to check. Thanks

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Post edited by: hwms, at: 2006/03/12 14:04

Higher elevations generally mean a bike will run richer. I know it sounds counterintuitive, but think of it like this the fuel delivered does not vary as much as the air does. At higher elevations there is less air and the mixture ends up being richer. At lower elevations the air is denser and because more air is available the mixture is leaner.

Don't ask me why the less dense air at higher elevations doesn't just draw less fuel. If it worked like this the system would stay in balance. Could it be that there is less oxygen at higher elevations? If so that would make better sense to me.

In any case the difference between 60 feet and 925 feet is insignificant, you'll never notice it while just road riding.

KZCSI

Post edited by: KZCSI, at: 2006/03/11 15:36

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Post edited by: hwms, at: 2006/03/12 14:04

At 925 ft you wont even feel the difference. Rule of thumb is the higher you go the less fuel you are going to need. So as elevation gets higher your carburation will get richer.

Post edited by: baldy110, at: 2006/03/11 21:54

Post edited by: baldy110, at: 2006/03/11 21:55

As altitude increases, atmospheric pressure decreases, air, being a gas, expands due to the lesser pressure, while the composition of the air remains the same.

Air weighs .0755 pounds per cubic foot at sea level, as explained above it will weigh less at higher altitudes. Air contains approx 21% oxygen, and oxygen is what the fuel combines with to cause combustion. So at sea level the motor will be getting approximately .02 lbs of oxygen per cubic foot, and at 10,000 feet altitude it will be getting approximately .014 lbs of oxgen per cubic foot of air. Since the fuel flow stays constant, and there is less oxygen, not all the fuel burns, ie the motor is running rich

A turbocharger solves the problem nicely :laugh: