2008 crf150r giving me fits...

So i bought this bike from a local on another forum that visit often. First starts up and it would have have the typical bog from the bottom when you hit the throttle. I took the carb off and rebuilt it. After that it would start up fine but when you hit the has it would just die. I went back through the carb and blew out the jets and still would just die when i hit the gas off idle. So i started playing with the air screw and once it was turned 3-3.5 turns out (stock is 2-2.5) it would run better but not good. I swapped out the plug and man what a difference, must have been the original plug. Took it out to the desert last weekend and it ran good and crisp. This weekend we hit the track and i fire it up for my son, warm it up and its good to go. He get on it 20mins later and now its bogging and cutting out on mid to full throttle and just dies. I blew out the jets, played with the air screw and played with the needle and no difference. Only thing i can think of at this point is the valves need to be adjusted. Anyone else have any issues like this on the older crfs with this fcr carb? Any tips would be appreciated.
thanks