This .020"- 2.4 degree offset flywheel keyway advances ignition timing for increased acceleration and horsepower. Caution needs to be used when selecting a keyway as more advanced timing can cause detonation without proper octane fuel. This keyway works well for most trail applications with good high octane fuel. This keyway works in all 600-800cc ZX, REV, and all Ski-doo 800R carbed and 800R ETEC, and the 850 ETEC
motors and all have achieved higher horsepower and torque with this keyway.