'01 YZ426f Elevation Jetting

1 reply to this topic
  • fmx09

Posted August 24, 2015 - 04:06 PM


I have an 2001 YZ426f and live in San Diego. I ride mostly in the surrounding desert so nothing ever above 2000 ft elevation. I am taking a hunting trip in a few weeks in the mountains of Idaho and am planning on using my dirt bike for transportation. Do I have to change the jetting for it to run up there? Will be between 7500-10000 ft. I don't mind if it runs a little funny as long as it runs. I just need it to get around up there. Thanks in advance.

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  • grayracer513

Posted August 25, 2015 - 05:44 AM


Based on rule of thumb calculations, an 8000 foot increase in altitude calls for a reduction in jet size of about 7% (slightly less than 1% per thousand feet), so by that, you'd need to go from, let's say a 170 to a 158-160 on the main, and from a hypothetical 42 pilot to a 39-40.

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