I got a question about altitude...

[trist007]

I have a 2006 KX-250 that I ride here in San Antonio, TX (elevation of about 600 ft). It has the stock jet, which is pretty rich cause my plugs foul often. Anyhow, my question is: If I take this bike up to Luna, NM which has an elevation of about 7000 ft, and ride it there on trails, would I need to get another jet? or would a simple adjustment of the air screw be sufficient?

 

[Flux3D]

The higher altitude you go the more rich your bike will run. This is because at high altitudes the air is less dense and you will therefore have less air mixing with the fuel. So if your bike is fouling plugs at 600ft it's only going to be worse at 7000ft.

 

[mideastrider]

I agree with flux3d its going to be worse. I would pack a few smaller jets just have when you get there. You may want to go ahead and drop a couple of sizes before you leave. Someone on here may can recommend what it takes for your bike at that elevation.

 

[jp2396]

I'm in Carson City, NV where the altitude is about 4,700' and I had to drop two sizes on the pilot from stock to stop fouling plugs here in the warm weather. You really need to get a correction factor chart and that will help you pick the correct jet for altitude/temp. Check your manual, it may have a chart in there. Mine didn't so I ad to google for one.

 

[BigRedAF]

At 7000msl you will be at 65% of sea level horse power.

Call a local dealer in the area or any area that is near that altitude and ask the service department or salesman that rides his KX250 around there what they are running.

An other idea is to call Pro Circuit and ask what they run at Mammoth Mountain on the bikes that they set up.

I'm guessing drop the pilot one size, raise the clip one groove which lowers the needle and drop the main three sizes and you will be in the ball park. The air screw only works in conjunction with the pilot when the pilot is in the range for your altitude.

Good luck...