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!!