Jump to content
Sign in to follow this  

need jetting suggestions at altitude

Recommended Posts

I am planning to ride at Sweetwater Nevada in a couple of weeks and need suggestions for jetting my 2006 CRF250X. I have opened the top of the airbox and modified the stock muffler. I am currently running a 155 main, 42 pilot, NCYS needle (4th clip), and 55 leakjet w/ the o-ring accelerator pump mod at elevations from 300' to 5000'. Sweetwater is 7000'-9000' and one ride will be to 12000'. Anyone have suggestions?

Thanks,

Share this post


Link to post
Share on other sites

I'd probably leave it alone. You will be absolutely fine on the majority of your riding.

I recently went to Colorado and did some passes, 13,100 the highest. Much above tree line and you had to keep it on the pipe or it would sputter. Especially if the terrain was robbing power. But even there the amount of time at extreme altitude as minimal.

If you really wanted to dink with it drop the main to a 150 and put the 40 pilot back in, drop the needle a clip. But dont do anything without leaning the pilot circut, it will be a waste of time.

Share this post


Link to post
Share on other sites

I went down to a 135 and the 4th clip and it ran pretty good (i think it could have ran better though), but I didn't have the r needle which I think you have...(maybe not). I also have not done the o ring modification. I was riding with the stock exhaust no mods, other than the airbox.

This was in elevation from 8,500-12,000ft.

Share this post


Link to post
Share on other sites

I'm thinking about a 140 main, 40 pilot and dropping the R needle a notch. Stock was a 130 main. What do you guys think.

Share this post


Link to post
Share on other sites

I have the same setup on mine and we just went riding in Idaho. I didn't mess with the jetting at all and it ran great. I don't think we got to 12,000' but we got to at least 10,000'. The 4 strokes are not as bad as the 2 strokes. My yz we had to jet down a little.

Share this post


Link to post
Share on other sites

2 weeks ago in CO., up to 13,000+

'06, 155m, NCYS, clip in 3rd, 42

Stock head/cam, full exhaust, cut open airbox

Ran perfect (except under water).

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...