I recently put a new top end on my 2002 cr250r and a jd jet kit. the jets are all stock spec but I have a 1/4 throttle rich and a 1/4 throttle lean needle from the kit. When I rev the motor I get surge after I let off. I put the lean needle in and it runs really good when I put the rich needle in it runs like crap. With either needle the problem remains. I let it idle and sprayed carb cleaner around the boot and case without any idle change. I opened the the stator cover and its very clean and dry. No residue in there at all. I put the jet kit in to try and eliminate the problem but it persists but I will say it added some throttle response. the reeds are in great shape. I dont know where else to look for the problem. I run 93 at 32:1. After I rev the motor I get 1 to 3 surges as the motor revs down sometimes it doesnt happen but just about every time it surges a little bit. Its a TMX carb and works well on the bike. If I could just get to the bottom of the surge I would be in there.