I would start by cross referencing the OEM variator part # with other 150cc Kymco scoots. This will give you an idea of the roller size. (18x16mm ect.) During that search you will most likely see the stock rollers, and their weight. Dr. pulley sliders seem to work better than rollers in some applications, and I believe this is one of them. They give a taller top end gear, as well as better take off. I would suggest 1gr. Heavier on sliders as they do increase rpm's by their nature. If you stick with rollers try 2gr lighter, and that will give great take off/ increased rpm's throught/ and hopefully keep your top end as is.
A Control or torsion spring in the clutch will also bring up the rpms, and hold the gear ratio lower till it tops out. Combined you will think you have a different bike. For the spring a 1000 is fine for a stock bike, and a 1500 is better if you have any mods at all (rollers/sliders). Any of the online parts lists will have the #'s you need.
