Compression springs do a couple of things. First they supply the pressure to engage the belt. They also determine the rate at which the CVT transmission changes from low to high gear. A 1000rpm spring will go into a higher gear than a 2000rpm spring.
This NCY 1000 rpm compression spring is specifically for the GY6.
Dimensions:
Spring I.D.: 48.5mm
Spring Height: 154mm
