Naraku Performance Variator Drive Face: 139QMB / GY6 50

Precision Grip: Naraku Machined Performance Drive Face

Eliminate belt slip and improve throttle response with the Naraku Machined Variator Drive Face. Engineered specifically for the 50cc QMB139 (GY6) engine platform, this high-performance component is the definitive upgrade for riders seeking smoother power delivery and increased drivetrain reliability. Unlike standard cast faces, this Naraku unit is precision-machined to ensure a perfectly flat contact surface, maximizing belt grip and efficiency throughout the entire RPM range.

Technical Performance Features

• CNC Machined Surface: Features a high-precision finish that optimizes the belt's contact patch, reducing friction-based heat and preventing power-robbing belt slip.
• Enhanced Heat Dissipation: The specialized anodized finish and optimized geometry help pull heat away from the CVT system, extending the life of your drive belt and variator rollers.
• 26-Spline Fitment: Manufactured to exact OEM tolerances with a reinforced 26-spline center, ensuring a rock-solid connection to the crankshaft.
• OEM Component Compatible: Designed to work seamlessly with your stock electric start, kick start components, and factory plastic cooling fan.

Comprehensive Fitment Guide

This drive face is a performance upgrade for the 139QMB / QMB139 engine family found in:

Technical Specifications

• Material: CNC Machined Aluminum
• Finish: Performance Anodized (Red)
• Spline Count: 26
• Vendor: Naraku

Mechanic's Note: The drive face is the outer half of your transmission's "pulley" system. 

Pro Tip: Over time, the stock face develops "grooves" from the belt that kill your top speed. Replacing it with this Naraku unit restores your original gear ratio transitions.

nstallation Hack: This face does NOT include the kick start gear or fan—make sure to swap those over from your old unit or grab a fresh Kick Start Claw if yours is worn!

SKU: 137-29
MPN: NK900.59
Vendor: Naraku