Hot Cams Valve Spring Kit Yamaha Raptor 660R The Hot Cams Valve Spring Kit provides improved throttle response and is compatible with Stage-2 (68-2067) and Stage-3 (68-2076) Hot Cams camshaft upgrades, available as a complete set. Features: Improved throttle response technology For use with Stage-2 (68-2067) / Stage-3 (68-2076) Hot Cams camshaft upgrade Sold as a set Specifications: Exhaust Spring Coil Bind17.780mm Exhaust Spring Installed Force55lb Exhaust Spring Installed Height30.607mm Exhaust Spring Maximum Lift11.430mm Exhaust Spring Open Force145lb Exhaust Spring Open Height8.763mm Exhaust Spring Rate270in-lb Intake Spring Coil Bind17.780mm Intake Spring Installed Force55mm Intake Spring Installed Height30.607mm Intake Spring Maximum Lift11.430mm Intake Spring Open Force145mm Intake Spring Open Height8.763mm Intake Spring Rate270in-lb