NCY Torque Spring (GY6), 1500 rpm
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 1500 rpm compression spring is specifically for the GY6.
Wire Diameter: 4.2mm
Inner DIameter: 48.5mm