RB carb

[101racing]

I'm wondering who out there has this mod done to there 300 and how they run ? I had the carb mod done and I can't get any response out of the air screw no matter where it is. It won't lean down enough to keep the motor clean when doing slow trail work. I'm down to a 38 pilot and 3.5 turns out on the air screw. I ride at 3800 ft and up. Do I need a different slide ? I have been around 2 strokes for many years and have tuned on them allot with great success. The motor runs very good other than extended slow work and then it loads up. Has anyone had the same experience ? Thanks