Is your 50cc 139QMB engine revving at its limit without a higher top speed? The RDLN 17/49 Performance Gear Set changes your final drive ratio from the stock 3.41�3.71 down to 2.88, allowing your engine to push the bike faster at lower RPMs. Depending on your engine mods and rider weight, this gear set can net up to 7+ MPH of top-end gain. It's also the essential final step for scooters running 72cc, 80cc, or 100cc big bore kits � eliminating the over-revving that comes with stock gearing on a bored engine.
Fits 139QMB / 1P39QMB engine cases found in nearly all 50cc 4-stroke Chinese scooters, including engines coded:
Installation Note: This is not a drop-in part. A hydraulic press is required to remove old gears from the secondary shaft and press the RDLN gears on. Professional installation is strongly recommended.
