Fit For 28T Timing Chain Cam Sprocket For 50cc 70cc 90cc For Pit Dirt Bike Quad Timing Smooth Engine Operation Fit For 28-tooth cam timing sprocket compatible For most 50cc 70cc 90cc horizontal four-stroke For pit dirt bikes ATV quads hardness with overall treatment reduces tooth abrasion deformation under RPM operation tooth profile ensures smooth meshing with timing chain, abnormal rattling timing deviation Standard inner bore spline mounting hole size match camshaft for direct press-on installation without Stable timing control prevents collision, hard starting power loss during daily trail riding