Bought my 03 RM250 new and after getting the jetting close to actually working (a real pita on the 03s) I still had a hard time dealing with the big mid-range hit when riding in these Ozark Mountain rocks. I called Varner Motorsports because I knew they were doing the motor work at the time for Suzuki Off Road (Smith, Kiedrowski and Hatch.) After reworking the head (I insisted on 92-93 octane only), shaving some material off the base of the cylinder, and porting work, it worked much better in the tight slippery stuff. Terry Varner insisted I stay close to my previous jetting specs, but it seemed too rich. Maybe because I only go 160 lbs, maybe because I short-shift and use the torque of the motor I'm rarely putting a big load on the bike like Team Suziki would, maybe Mr Varner was being overly cautious with his jetting recommendations...? I've done searches within this forum and before my motorwork I was right where most of you are with jetting on the 03s, but after the cylinder and head work I'm always 1-2 sizes leaner with the pilot, JD red needle in recommended 4'th slot until over 70* (then I go to 3'rd slot), usually a size leaner on the main too. Ever hear of having to lean things out when porting/head work is done? I guess it's because the motor is breathing better?