My gy6 overheats a lot?

I have either an '04 or an '05 Twister Hammerhead 150cc. It has a gy6 clone. Is it extremely common for these motors to overheat like, every time you use them for more than 20 minutes? I guess i drive it hard, but i dont floor it constantly and when i can, i try to keep the rpms from going through the roof. But every single time i use it for about 20-25 minutes, it starts to pop when i let off the gas and it sounds like it backfires. Also, about 10-15 minutes after that, it starts to sputter when i push it past a certain point on the throttle. and if i push the gas much harder, it'll stall. i'm almost 100% sure this is from overheating. but i just don't think it's right that an engine should overheat and suffer terribly after 30 minutes. Do you other gy6 owners have this problem? would getting a uni high flow intake help? or just shove more air and fuel in faster so it overheats faster? Could the spark plug be starting to go bad and not work when extremely hot? i haven't done any performance mods to it by the way.