[Alex.Norton]

The brass fins are weights that are used to shift the cvt from a high ratio (high input to low output) to a low ratio. When the input spins fast they pull out causing the pulley they are on to close making the radius of the pulley higher this causing the ratio to get higher. When the input slows du to a larger amount of torque being need the weights are pulled in by a spring and opening the pulley making the ratio lower.

At least that is what I get from the pictures.