Aerox bogging problem

Hi I have a Yamaha aerox Valentino Rossi rep and it has a Leo vince tt exhaust and new piston and barrel but it seems to be struggling to hit high revs sounds more like a 4stroke than 2 but when I put it on the stand it takes a while but hits the high revs ? Any idea what the problem could be?

 

Rollers too heavy?

 

It use to run fine till I put new barrel and piston on ?

 

Play around with the jetting then. Also check everything is assembled correctly, any air leaks around base gasket? Head gasket? Piston right way round? Head nuts torqued up?

 

Okay thanks

 

also i may add if its had a new barrell and piston you should't be full throttle'ing it or giving it too much still untill its run in

 

stick not still lol