[SLESTAK75]

To add to what SYCARMS said. The front pulley is i 2 halves, a stationary and a sliding. The sliding half has ramps in the backside with weights in them. As the rpms increase the weights are thrown outward by the centrifugal force and they ride up the ramps. This pushes the two halves together and causes the belt to ride up the pulley ramps increasing the gear ratio. Heavier weights start moving at lower rpms and lighter at higher. So the weight of your rollers determines the rpm at which your shift starts and also the rpm held by the engine during the shift. The rear pulley is controlled by a spring. More tension= slower shift/ less tension= faster shift. There is a balance to be had and the weight you choose is determined by your own preference. On average most choose the 1500 rpm contra spring and 10 to 12 gram weights. There are roller weights and slider weights ( different shape-same function ) I feel that the slider weights are more effective than the rollers. On the black smoke, if the auto choke is bad then replacing it should fix the problem. Check the wiring and make sure there is voltage going to it. If there is then plug it up ( make sure its cold ) and measure the needle, start it and let it run for 8 mins or so and measure the needle again, it should be longer now. If not it isn't working. I posted a video that lets you see the CVT in action to help clarify.

http://www.google.com/url?sa=t&rct=j...,d.dmQ&cad=rja