High altitude performance

[JBaldwin]

Hello forum,

I am the new owner of a low hour but not well maintained 2001 kdx200 (still had O.E rear tire with about 1/4 tread left). The bike is stock for now, though I have replaced the usual wear items and put on new tires.

I live in the scenic San Juan mountain range at 9000 feet above sea level. Most of my riding is adjacent to my home at 10,000-11,500 feet. I am also an hour away from Colorado's alpine loop which has several passes nearing 13,000 feet.

I would love to hear from anyone who rides/has riden at these elevations and could give me an idea of how much the performance is affected. Any jetting recommendations would be appreciated as well.

I am asking these questions because the bike seems down on power vs what I have seen and read online. The bike is jetted pretty well and has good compression. It lugs very well and accelerates briskly in the upper gears, yet is slow to accelerate past 50mph and does not want to wheelie with this 240 pound rider aboard. For comparison sake my Honda 250 four stroke (jetted for elevation) is a complete turd compared to being at sea level. Is there much more to be gained or am I close.

Thanks, James

[SS109]

Sounds about right from what I've read. Highest I've ridden is about 7000. My normal rides are around 2000 and the power difference is noticeable but not extreme. I hear above that and power really starts to decline. At your kind of elevation I would probably want a 300 2T or one of those 500AF conversions.