riding in high elevation

[Tippy]

If one doesnt re-jet for high elevation, how much of a difference will it honestly make if you're riding above the prescribed elevation for your jetting?

[Dune Dude]

It depends on how much elevation change your talking about.  Grants Pass is aprox. 1000ft. above sea level.  The KFX's run just a tad rich at home, but are just about perfect at the coastal sand dunes.  I would never be able to detect any difference in performance for my riding style and ability.  If I took the KFX's to St. Anthony's with its elevation of over 4500 ft. i would notice a big difference in performance.  Even if the jetting was done spot on the lack of air will cause about a 10% loss of power.  If I did not re-jet, the beast would run very rich and probably foul the plugs in just a short amount of time.  If the KFX has around 44 hp a loss of 10% is 4.4hp which is very noticeable in an ATV.

For the casual rider jetting will not be as important as it is for the MX or XC racer at any slight change of elevation.  Racers change the jetting and tune the ATV to gain the last bit of hp they can at every track they go to. 

Having the ATV properly tuned also, makes a big difference in how loud the exhaust is.  The tests of exhaust systems in magazines like our favorite, Dirt Wheels, are done on an ATV that is tuned to the attitude and weather conditions it is in during the test.  So if it says it registered a 94 db on a particular pipe and you put it on your ATV that is not running at its best your sound could be considerably higher.

[DuneJunkie]

My bike was jetted and dyno'd at the coast...............i take it to Diamond Lake every year and run it up there on the mountain in the snow and it doesn't miss a beat!