Razor Sprocket and Freewheel for MX500/MX650/RSF350/SX500

Drive System Restoration: Razor Sprocket & Freewheel Restore the smooth power delivery of your electric dirt bike with the Universal Parts Sprocket and Freewheel Assembly . Engineered specifically for high-torque Razor motors, this complete unit replaces worn, slipping, or "frozen" rear drive assemblies. By combining a precision-machined sprocket with a heavy-duty internal freewheel, this assembly ensures your chain grabs instantly during acceleration and coasts freely when you let off the throttle. Technical Performance Features Complete 3-Piece Assembly: Includes the drive sprocket, high-engagement freewheel, and a protective outer guard to prevent chain derailment or debris interference. OEM Thread Precision: Features a standard M34 x 1.00 thread pitch for a seamless "spin-on" installation to your factory rear wheel hub. Durable Steel Construction: Designed to withstand the high-torque demands of 500W and 650W motors without premature tooth wear. #25H Chain Optimized: Specifically profiled for #25H "Heavy Duty" chains, ensuring maximum contact area and reduced mechanical noise. Comprehensive Fitment Guide This assembly is a direct-fit replacement for the following Razor electric vehicles: Model Family Version Compatibility Razor MX500 / MX650 MX500 (V22+) / MX650 (V15+) Razor SX500 / McGrath Versions 1 and up Razor RSF350 Electric Sport Bike (Standard Fitment) Razor MX350 / MX400 Compatible with select mid-frame versions Technical Specifications Chain Size: #25H Thread Pitch: M34 x 1.00 Outer Diameter: 7 Inches Cross-Ref Part #: W15165070142, W15128199013 Mechanic's Note: If your motor is spinning but the rear wheel isn't moving, your internal freewheel has likely failed. Installation Hack: These are "spin-on" parts that tighten as you ride. Pro Tip: To remove the old one, you may need a Freewheel Removal Tool or a hammer and punch—don't forget to apply a small amount of anti-seize to the threads before installing the new unit to make future service easier! SKU: 119-241 Vendor: Universal Parts