98 speedfight 100 wont pull away?

my speedfight wont pull away when it is on its stand it starts first time and under revs the back wheel turns easy and at high speed however when i sit on the bike and try to pull away the engine does not rev high enough to do any thing to make the back wheel turn i have replaced the air filter, sparkplug, coil, ht lead and cleaned all of the jets and float in the carb and i am running out of ideas