Polini 50mm Piston Kit – QMB139 / Kymco Agility – Part #204.0929/B

Polini 50mm Piston Kit is a genuine high-performance replacement piston for QMB139 and Kymco Agility 4-stroke engines. Designed for use with Polini’s 50mm big bore cylinder kits, this piston offers precision engineering, excellent heat resistance, and long-lasting reliability.

Perfect for rebuilds or maintenance of existing Polini 50mm performance kits, this piston helps restore compression and engine power while maintaining the exceptional performance standards Polini is known for.

Features:

• Genuine Polini Italy performance piston kit

• Replacement for Polini 50mm big bore cylinders

• Designed for QMB139 4-stroke engines and Kymco Agility 50

• Precision-machined aluminum piston for durability and heat control

• Restores compression and maintains factory performance

• Ideal for rebuilds, maintenance, or upgrades

Specifications:

• Bore Size: 50mm

• Part no 204.0929/B

• Wrist Pin Diameter: 13mm

• Compatible Engines: QMB139 / GY6 50cc / Kymco Agility 50 4T

• Material: Forged aluminum piston with polished crown

• Engine Displacement (with stock stroke): Approx. 81cc

Includes:

• Piston

• Piston Rings

• Wrist Pin

• Circlips (x2)

Compatibility:

• QMB139 50cc 4-stroke engines

• GY6-based scooters