I would first check the airfilter and jets in the carb to see if they need cleaning . Popping from high RPMs is lean misfire which means your a lil lean . To fix that you simply replace the factory main jet with a size or two larger on like in this jet kit here
http://www.partsforscooters.com/114-...ategory=133078
You need to remove the CVT and then the variator in order to remove and weigh the rollers to see you have . A gram or two lighter can help on take off and uphill and often top end if the RPMs get higher than with heavier ones . Too light and you will loose speed . Get a weight set kit like here so you can try various weights
http://enviromoto.ecrater.com/p/1417...ht-kit-18-x-14
Could have some cloggage in the exhaust pipe . Does your needle in the carb have an adjustable clip ? Do you have an air/fuel screw that you can adjust ?
Here is some tuning tips
http://www.provoscooter.com/tuning