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High Altitude / Rockies

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I"m headed out to Taylor Park and Ouray next week. If anyone rides their bikes out there could you shoot me your jetting specs just so I can get a starting point ? My sons ride is a 2002 yz250f. Eleven ,twelve thousand feet is up there. Thanks

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A JD jet kit has all of the necessary jets and a chart to help dial in your jetting for just such a trip. I've always used them in the past with great success, and highly recommend them. I lived in Montana for a few years, and used the JD on my WR450, and it worked perfectly. But since your short on time, you can check out the jetting data base "sticky" at the top of this forum, and find some recommended jetting and give that a try.

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I went to those altitudes (from sea level) last year. Silverton, Telluride, Ouray, and points in between. I dropped my main one or sizes (e.g. 180 - 175 or 170, I forget the actual) , and the pilot from 45 to 42 on both WR250Fs. My son has a WR450F, and he didn't bother jetting, and he was actually fine. Compared to two strokes, these bikes aren't very sensitive to jetting IMHO. Remember, you will lose power, and you can't create oxygen by jetting, so don't bother trying.

Maybe I could have jetted a little better, but I spent my time riding, and it was well worth it.

-Toby

Edited by Toby_S

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I've been there a few times and my best settings were 1 size leaner on the pilot and 2 sizes leaner on the MJ and needle moved to 2nd to leanest. That particular trip i was on a 02 wr250f with yz cam timing. I ended up with 38PJ, clip on 2nd from top for needle and 2 sizes down on MJ. I think it was like 170 or 173.

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That's right. I moved the needle down 2 notches too.

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I just rode Taylor with my '03 WR this weekend and had good results with:

MJ: 162

PJ: 42

LJ: 90(stock)

Needle: stock, raised the clip a notch from middle position

It ran great, but it could have used a smaller LJ. Bog was minimal...don't use a smaller pilot than a 42. It is counter intuitive but it is what works for theses bikes at altitude.

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