39mm QMB139 Engine Kit with 69mm Non-Emission Head

Upgrade your 50cc scooter or ATV with this comprehensive 39mm QMB139 engine kit, featuring a high-performance 69mm non-emission cylinder head. Designed for enhanced power and efficiency, this kit provides essential components for a robust engine rebuild or performance enhancement.

• 39mm Piston and Cylinder Bore: Delivers a precise 39mm bore for optimized combustion and increased displacement over standard 50cc engines.
• 69mm Valve Length: Equipped with 69mm inlet and exhaust valves, ensuring superior airflow for greater power output.
• Non-Emission (Non-EGR) Cylinder Head: Features a non-emission design for improved performance without sacrificing environmental compliance.
• Complete Variator Kit: Includes a variator with 62 drive face teeth, 26 splines, an 87mm outer diameter, and 8.5g rollers for smooth acceleration and optimal gear ratios.
• Performance Carburetor and Air Filter: Comes with a 19mm intake carburetor and a 38mm inner diameter performance air filter for better fuel-air mixture and intake efficiency.

Compared to standard GY6 50cc engines, this 39mm kit offers a significant displacement increase, leading to noticeable gains in torque and top-end speed. Its non-emission cylinder head design, combined with larger valves, allows for better gas exchange, which is crucial for performance-oriented builds that often surpass stock capabilities and previous model limitations.

Key Technical Advantages: Technology and Performance

This engine kit integrates advanced components engineered for superior performance in QMB139 and GY6 50cc applications. The 39mm bore, paired with the optimized cylinder head featuring 69mm valves, maximizes volumetric efficiency. Coupled with a high-flow carburetor and variator system, it ensures that your engine operates at peak potential, providing responsive power delivery and enhanced durability for demanding ride conditions.