Naraku 47mm Performance Piston Kit is a high-quality replacement piston designed for QMB139 50cc/49cc 4-stroke engines equipped with a 47mm big bore cylinder. This kit restores lost compression and ensures smooth engine operation — ideal for rebuilds, repairs, or routine maintenance on your performance setup. When paired with a stock 41.4mm stroke crankshaft, this piston provides a total displacement of 72.8cc, delivering a noticeable increase in power and throttle response while maintaining everyday reliability. Features: Genuine Naraku performance replacement piston kit Designed for 47mm big bore cylinders (72cc conversion) Precision-machined aluminum piston for durability and heat dissipation Restores compression and maintains OEM-level reliability Ideal for rebuilds and performance upgrades Specifications: Bore Size: 47mm Wrist Pin Diameter: 13mm Piston Height: Approx. 36mm Compression Height: 20mm (center of wrist pin to piston crown) Works with stock 41.4mm stroke crankshaft (72.8cc total displacement) Compatible with QMB139/GY6 50cc 4-stroke engines Includes: Piston Piston Rings Wrist Pin Circlips (x2) Compatibility: QMB139 50cc / 49cc 4-stroke engines GY6-based scooters
