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:

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