My peugout speedfight 2 50 is nt running rite?

My peugout speedfight 2 50 isnt running rite i added a doppler sports exhuast and sports airfilter i added the bigger main jet but i think it might still be to small when im riding it it dosent rev out to its full and gose really slow intill i go down hill then it tears and also when i go off from a standing start it flys for a sec then slows rite down