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2002 Honda CR250R at altitude

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Anyone running one at altitude?

Currently stock jetting

Bike: 2002 Honda CR250R

Altitude: 9000-12000ft

Temp: 60-70 degrees

Mods: FMF Gnarly, FMF Spark Arrestor

We are going to Crested Butte on Fri. and my Brother never re jets for it, I think we should this time, I'm tired of waiting on him to change plugs.

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I have a 2001 CR250R. I run a 15 pilot jet, S-7 needle jet, 6BEH2-76 needle in the second clip for altitude and a 380 to 400 main, depending on temperature. For low altitude in the winter I run a 17.5 pilot jet, set the needle to the third position and run a 410 main. But even more important for trail riding is to use a better spark plug. I use an Autolite 404. Their cheep but fire through a rich mixture much better than the BR8. They have a heat rating simular to a BR6 but I have yet to errode or short one but you need to keep an eye on it incase your riding style is to hot for the plug.

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GreenKLX,

The pilot jet is usually closer to a #30 when stock, so the #15 seems extremely small.

A #360 to #380 main jet and clip position #1 or #2 would be a good estimate for 9000ft. Turn the air screw outwards to lean the idle mixture if you're running the stock pilot jet.

James

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i agree that 15 is way small.

380 main jet,32.5 pilot jet was stock in 02. 350 main jet,clip 2,27.5 pilot for 9k..

That sounds about right, thanks Eddie. What do you think for when we get back to sea level? It seems to run fine with stock jets, but I don't ride 2 strokes much.

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I know its stock, but I have no idea what stock is. I will find out tonight.

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I know 15 is very small but even a 17.5 makes it idle rich. I am suspicious that mikunie carbs are not built that accurately and as a result each one takes a lot of brass to get it running right. I understand the 2002s are better carbed.

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