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Wyoming riders. . .

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Hey guys I got a question for a friend. He moved to Wyoming and he just got his bike over there. It's a 2003 yz 125. He sits at 4800 feet in elevation and his bike is slugish and only runs true when he's "on the pipe" as he says.

Any way he knows he needs to rejet but not sure what to. We're both assuming its on the stock jetting an needle clip. He used to ride here in Washington with me at damn near sea level.

What do you think he should re jet to? Change the main and pilot and needle? Im thinking changing the needle up a clip right? but then again im no pro on carbs.

Also his bike isn't a pile or nothing. he takes good care of it and cleans the filter all the time. the bike is in good shape and ran fine in Wa, but we know it just the elevation change.

Any help would be nice, thanks:thumbsup:

-Brady

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Yup he needs to re-jet.. Smaller main, maybe a different needle and a smaller PJ, re-adjust the airscrew.

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Id look in the jetting forum. Or you can find a jetting chart in the interwebs, once you know whats in the bike now.

And...its best if the bike has a fresh top end. Trying to jet a bike with a worn out motor is no bueno.

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94% is equal to 3000 Ft......

Start with the math, buy the jets, and then move the clip position. Take the main jet size (and Idle jet size), multiplied by .94 (94%), and thats a start. It is a different percentage for the different altitudes, so figure out what altitude he will be riding in.

I ride most of the time, at 4000 to 6000ft. I used the 94% figure so that I'd be safe, when I go to the dunes, which is 3000ft.

The air screw is often over looked. Just because somebody says to have it 1 1/2 turns out, doesn't mean that is where it performs the best. People in my altitude suggest 3 1/2 turns out. Right now, I am close to 3 3/4 turns out. I am changing it with different temps, weather conditions, altitudes, fuel quality, etc. (The engine will tell you what is correct, once you start listening....)

Good luck.......

(I am sure that someone will argue this, but it has worked for me, for a long time. Take it for what it is worth.......)

Edited by BlueLightRhyno

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