Ok Guys lets see if any of you can figure this concern out.It's a cheetah power valve top end with stock cr 250 reeds,32mm flat slide carbs,plate set at+4,270 main jets 48 pilot jets needles set in third notch.What happens with this is when I ride it under half throttle it runs great but as soon as I go to half throttle or more it will fall flat on its face and actually almost stop completly.Let me tell you first off that I have allready figured it out but I would like to see if any one else can figure it out,Also buy installing 1.8 air jets in the carbs it helped considerably,HOWEVER THIS PROBLEM IS NOT CARB OR SPARK RELATED.So lets have some fun and see who else may be able to figure it out.