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: Vehicle Series Specific Model Applications (Version 1+) Razor Dirt Rocket MX350 Dirt Rocket, MX400 Dirt Rocket (All Colors/Variants) Razor Electric Sport RSF350 Electric Sport Bike 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