SSP-G GY6 52mm Cylinder with Head Kit | 88cc Big Bore Upgrade for QMB139 Engines (169-536)

The SSP-G 52mm Cylinder with Head Kit is a complete big bore upgrade designed for QMB139 50cc 4-stroke engines, increasing displacement to 88cc for a major boost in power, torque, and acceleration. This kit includes a high-flow cylinder head with 64mm valves, engineered to deliver improved airflow and combustion efficiency — perfect for riders who want reliable street performance or a stronger take-off on hills and traffic.

Built from precision-cast aluminum with a durable iron sleeve, this SSP-G kit offers superior heat dissipation, strength, and long-term reliability. It’s a direct bolt-on upgrade for most 50cc GY6/QMB139 engines and is compatible with stock crankshafts and CVT components.

Features:

• Complete big bore cylinder and head kit for QMB139 50cc engines

• Increases displacement from 49cc to approximately 88cc

• Includes high-flow 64mm valve head for better air/fuel efficiency

• Aluminum cylinder with iron sleeve for maximum cooling and durability

• Direct bolt-on design — no case boring required

• Ideal for performance builds, commuters, and sport-tuned scooters

• Compatible with stock camshaft, carburetor, and exhaust systems

Specifications:

• Brand: SSP-G

• Product Name: 52mm Cylinder with Head Kit

• Part Number: 169-536

• Bore Size: 52mm

• Valves: 64mm (Performance Head)

• Engine Type: QMB139 4-Stroke (GY6 50cc Platform)

• Material: Aluminum Cylinder / Iron Sleeve

• Displacement After Install: ~88cc

Compatibility:
Fits most Chinese-made 50cc scooters with QMB139 engines, including: