Hoverboy 10 Posted November 4, 2004 Hello everyone! I have a question about the jetting on my 99 XR 250R. It runs very rich, and will nealy fowl the stock NGK spark plug during each ride. After I ride it for a little while, it will sputter and bog at high RPM. It has a UNI Filter, the snorkel off the airbox, but otherwise is stock. When I check the plug after a days ride, it is black with carbon. my altitude where I ride is 1,100 feet asl. I ride just outside of Phoenix, AZ. What size jetting do I need to make it run leaner? I mostly ride desert trails, with an occasional jump here and there. I just bought this bike used. I will be making it street leagal soo, and I will post some pictures. Thanks!! Share this post Link to post Share on other sites
ID_XR250 10 Posted November 5, 2004 Sea Level 135M/45P 4000-6000 ft 130M/45P 6000-8000 ft 125M/45P 8000-10,000 ft 125M/42P above 10,000 ft 122M/42P Share this post Link to post Share on other sites
team_burk 41 Posted November 6, 2004 ID_XR250's chart looks good. However, you only show mods on the intake side and nothing on the exhaust side. Stock jetting may be a solution for the sea level up to 4000' entry, 45 pilot, 132 main. What is your present jetting? Share this post Link to post Share on other sites
