Chain Tensioner for Razor MX350, MX400 Dirt Rocket / RSF350

Restore proper chain alignment and prevent dangerous derailments with this Universal Parts Replacement Chain Tensioner Assembly. Specifically engineered for the Razor Dirt Rocket and Electric Sport Bike series, this spring-loaded tensioner automatically maintains optimal chain tautness across rough terrain, protecting your motor sprocket and rear drive assembly from premature wear.

A failing or bent chain tensioner causes excessive chain slap, decreases battery efficiency, and can cause the chain to jump off completely during sudden acceleration.

Product Features

• Direct OEM Specification Match: Manufactured to match the exact fit and spring rate of Razor factory part number W15128050079.
• Durable Construction: Heavy-duty steel bracket arms and a high-density composite roller wheel engineered to withstand dirt, mud, and vibration.
• Complete Setup: Arrives as a unified bracket assembly ready to mount directly into the factory chassis bracket.

Technical Specifications

• Manufacturer Part Number (MPN): W15128050079
• Type: Dynamic Spring-Loaded Roller Tensioner
• Material: Zinc-plated steel housing with an impact-resistant composite roller.
• Hardware Note: Reuses factory frame mounting bolts.

Model Fitment & Compatibility

This replacement assembly is verified for all manufacturing versions (Versions 1+) of the following Razor electric platforms:

Tech Tip: While replacing the tensioner, always inspect your rear wheel alignment and check your chain for stiff links or excessive stretching. A worn-out chain will continue to jump even with a brand-new tensioner installed.

California Prop 65 Warning

MX350 Dirt Rocket, MX400 Dirt Rocket,