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
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Complete 3-Piece Assembly: Includes the drive sprocket, high-engagement freewheel, and a protective outer guard to prevent chain derailment or debris interference.
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OEM Thread Precision: Features a standard M34 x 1.00 thread pitch for a seamless "spin-on" installation to your factory rear wheel hub.
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Durable Steel Construction: Designed to withstand the high-torque demands of 500W and 650W motors without premature tooth wear.
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#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 |
Features
- Complete 3-piece assembly — sprocket, freewheel hub, and outer guard ring with hardware
- #25H heavy-duty chain optimized — maximum contact area and reduced noise
- M34 x 1.00 thread pitch — spin-on installation to factory rear wheel hub
- Durable steel construction — handles 500W and 650W motor torque demands
- Direct-fit for Razor MX500 (V22+), MX650 (V15+), RSF350, SX500, select MX350/MX400
Specifications
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Chain Size: #25H
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Thread Pitch: M34 x 1.00
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Outer Diameter: 7 Inches
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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
Model Fitment
Razor MX500 (V22+), Razor MX650 (V15+), Razor SX500 / McGrath (V1+), Razor RSF350, Razor MX350 / MX400 (select versions)
