RK Racing Chain 4044-040SG Steel Rear Sprocket and GB520EXW Chain OE Replacement Kit Fits: Yamaha YFZ450 (Quad) carbureted 04-09 and 12-13 OE replacement kit contains: 14 tooth chromoly front sprocket; 38 tooth steel rear sprocket; and RK GB520EXW-96 link gold chain Sealed XW-ring chain features heat treated high carbon alloy steel components with seamless rollers and shouldered bushings providing the user with a 50 percent longer wear life than basic O-ring chains XW-ring uses an advanced nitrile butadiene composite and features three contact lips and two convex outer stabilizers; this means three lubrication pools to protect against high speed abrasion, extreme heat build up, torsional flex and loss of lubricant XW-ring chains are the best high-speed, extreme heat performance chains available today and include a clip type master link