I have a yahama 2 stroke 80cc that is not running full speed. It will really crank on first and second gear but when i hit third gear going about 20 mph it just looses that "crank" or like power i guess. We tried cleaning the carb and choke because we thought that the engine was not getting enough gas or air because it was dirty. but that didnt help. Now i dont know what i should try cleaning or adjusting to get it running correctly. any ideas?