Restore lost top speed, eliminate off-the-line bogging, and completely refresh your drivetrain with the Naraku Super Transmission Kit. Engineered specifically for 50cc and 49cc GY6 50 / 139QMB 4-stroke engines, this all-in-one CVT tuning package replaces your entire worn factory transmission setup. By matching a high-performance variator, precision-balanced clutch assembly, heavy-duty clutch bell, and a calibrated drive belt, Naraku delivers seamless linear shifting, crisp throttle response, and maximum power transfer to the rear wheel.
GY6 50cc engines come in three distinct case lengths. Use the drop-down menu to select the correct kit configuration for your scooter platform:
Tuning Note: The included 6g roller weights provide an excellent balanced starting point for stock or lightly modified 50cc engines. If you have an 80cc Big Bore Kit installed, experiment with heavier or lighter weights to match your modified torque curve.
Installation Tip: Clean the crankshaft splines carefully before installing new components. Never use an impact gun to tighten the variator or clutch nuts without a holding tool � improper torque can strip crank threads or crush components.
Naraku is a German performance brand specializing in high-quality CVT and engine components for small-displacement scooters and mopeds. Known for tight manufacturing tolerances and rigorous quality control, Naraku parts are a trusted upgrade over OEM for riders who demand more from their 50cc platform.
SKU: 137-1 | Vendor: Naraku | Category: Engine & Transmission / Complete CVT Kits
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