Hi Carvets-
Belts are cheap, so there's not much downside in trying other brands. I find that Gates & Bando belts are easy to locate and work as well as any other brand. The main job skill needed is the ability to measure the circumference of the belts. Weights also are cheap and worth the time to experiment. In general, the lighter the weights, the quicker your machine will accelerate. Weights have no effect on top speed. In most cases, Kawasaki ATVs use the same drive parts as Kymcos, so if you can't find a Kymco source, check your local Kawasaki dealer.