Take apart the carb and clean every ( and learn to do this in your sleep) part in it. Take apart the petcock and fuel line clean or replace it check for leaks in intake and gaskets. clean and check and gap points.( you inspected and cleaned and gaped them when you got your bike right ?) know how to check timing. clean gap and change plug ect. If you can't do these things pay a moped or motorcycle shop to do them for you. If is not a engine bogging power loss problem it could be clutches. If it is not shifting ( its full of tranny fluid right ?) correctly then good luck- that would cost hundreds to fix