I have had my trx for almost a year now its been working great i put a full hmf exhaust an air filter and i got a dyno jet kit stage 2 i followed the instructions and just changed the main jet ..its been working fine but i feel that it can go much faster at top speeds and it starts choking and popping at 5th gear max speed??? how can i stop that and get more top speed??open the airbox?? help plz