Fits the 139QMB / QMB139 engine family found in most 50cc 4-stroke Chinese scooters:
Compatible With
Engine codes: 139QMB | 1P39QMB | 139QMA
Brands: TaoTao, Wolf, Ice Bear, Bintelli, Kymco, SYM, and other GY6 50cc platforms
Material: CNC machined aluminum
Finish: Red anodized
Spline Count: 26
SKU: 137-29 | MPN: NK900.59
Eliminate belt slip and improve throttle response with the Naraku CNC Machined Performance Variator Drive Face . Engineered specifically for the 50cc QMB139 (GY6) engine platform, this red anodized aluminum drive face is precision-machined to ensure a perfectly flat contact surface, maximizing belt grip and efficiency throughout the entire RPM range. A direct upgrade over the stock cast face, which develops grooves over time that kill top speed and gear ratio transitions
Product Details
CNC Machined Surface: High-precision finish optimizes the belt's contact patch, reducing friction-based heat and preventing belt slip
Red Anodized Finish: Specialized anodizing improves heat dissipation, extending the life of your drive belt and variator rollers
26-Spline Center Hub: Manufactured to exact OEM tolerances for a rock-solid crankshaft connection
OEM Component Compatible: Works with stock electric start, kick start components, and factory plastic cooling fan
Model Compatibility
Key Features
Technical Specifications
Important Notes
Mechanic's Note: The drive face is the outer half of your CVT pulley system. Over time, the stock face develops grooves from the belt that kill top speed — replacing it with this Naraku unit restores original gear ratio transitions. Note: Does NOT include the kick start gear or cooling fan — swap those over from your old unit during installation
Shipping & Use Restrictions
California Prop 65 Warning: www.p65warnings.ca.gov
