This NCY adjustable secondary sliding sheave has two sets of ramp angles,
one steeper than the other.

These allow you to adjust how quickly the pulley engages. A quicker engagement means more power off the line, and more gradual engagement gives you more power at speed.

This is a major  performance improvement!

(using genuine yamaha parts is over $300 and does not have the performance)

In the clutch diagram, this replaces parts numbered:

5 ,6, 7, 8, 9, 10, 11, & 15