Pro Taper Race Spec MX Front Sprocket Yamaha/Kawasaki 250-450 (98-04). ProTaper Race Spec (RS) Front Sprockets are CNC machined and internally broached to precise tolerances from case-hardened, core-refined chromoly steel. Computer engineering ensures precise fitment, optimal weight savings, and perfect balance. The result is minimal chain drag, maximum horsepower, and uncompromising strength. A proprietary coating further reduces wear and- Pro Taper Race Spec MX Front Sprocket Yamaha/Kawasaki 250-450 (98-04).