Secondary Gear Kit NCY 18/46 for GY6 139QMB/QMA

The NCY QMB139 upgrade kit for your 50cc 4-stroke is finally here! This kit is specifically designed for big bore engines and increases your gear ratio by 26%. This will allow you to maximize your big bore kit by increasing top speed and a more usable RPM range. You won't see much, if any, performance improvement if you install these on a stock top end. For experienced tuners only.

The NCY QMB139 Upgrade Kit for your 50cc 4-stroke is finally here! This kit is specifically designed for large bore engines and increases your gear ratio by 26%. This will allow you to maximize your large bore kit by increasing top speed and a more usable rev range. You won't see much, if any, improvement in performance if you install them on an original high-end. For experienced tuners only.

Specifications:

• Type: Secondary
• Ratio: 18/46 (2.55)
• Assembly: Press