GY6 50cc / 50cc (139QMB) High-Speed Gear Set (17/49)

High-Speed Gear Set for GY6 50cc and 139QMB Engines

This high-speed gear set is designed for 50cc engines, specifically the 139QMB. It alters your final drive ratio, improving efficiency to a more effective 2.88. This adjustment allows your engine to achieve higher speeds at lower RPMs. It is one of the GY6 50cc scooter parts that can help you gain up to 7+ MPH, especially beneficial for those with upgraded engine kits.

Performance Improvement

The gear set's 17/49 configuration optimizes the balance between acceleration and top speed. This is especially useful for scooters equipped with 72cc, 80cc, or 100cc big bore kits, helping to eliminate over-revving that often occurs with stock gearing. Riders can enjoy a noticeable increase in cruising speed while reducing engine strain.

Precision Engineering

Made from forged and hardened steel, this gear set is precision-cut to handle the demands of high-performance engines. The choice of material ensures reliability under increased torque, making it a valuable upgrade for performance-focused riders. Installation requires special tools, as a hydraulic press is necessary to replace the original gears.

Specifications

• Teeth Count: 17T pinion / 49T large gear
• Final Drive Ratio: 2.88
• Material: Forged hardened steel
• Installation: Requires hydraulic press

Fitment

This gear set is compatible with 139QMB and 1P39QMB engine cases found in various 50cc 4-stroke scooters. It fits engines coded as follows:

• Standard GY6 50: 139QMA, 139QMB, 1P39QMB, 1P39QMA-2
• Extended Codes: YN139QMB, JJ1P39QMB, 139FMA-2, BD1P39QMB, BN139QMB, 147QMD
• Popular Brands: TaoTao, Wolf, Bintelli, Ice Bear, Kymco (select 4T), SYM, Lance

Not sure it fits? Contact us with your scooter's make, model and year and we'll confirm the fit before you order.

Shop more: GY6 50cc Scooter Parts (139QMB) · GY6 Scooter Parts · Scooter Transmission & Final Drive · Scooter Parts