01 250 jetting
Good jetting requires some experimentation on your part. It only takes a few minutes to change the jets/needle/clip position. Get a 40 & 42 pilot, a 170 & 172 main and the next step leaner needle. My EXC came with 172,175,180 mains, 42,45 pilots and NOZG,NOZH needles. I live in Illinois at about 700 ft and was running a 40 pilot and 172 main with the NOZH needle in the middle clip position. This worked well enough in the woods at low throttle settings and no fouled plugs. I'm currently riding in Colorado at altitudes ranging from 4,000 to 13,000ft and temps from 80 to 50 degrees. On the first day here I rode to an elevation of about 10,000 ft. The bike was running very rich everywhere. I stopped, got out the tool kit and changed jetting right there. Put in a 40 pilot, 170 main, moved the needle clip one position leaner and put in a fresh plug. The jetting is still a little fat at altitudes above 9,000 ft but it 's close enough below that. The point is that if you just let others advise you on what jetting to run you'll never learn anything and will probably need to start buying spark plugs in bulk. A final note, and none of this is meant as a personal attack. Only fools ride without tools. At least take a plug and plug wrench along.