RDLN A9 Performance Camshaft – GY6 50cc / 139QMB (High-Lift)

Stage 2 Power: RDLN A9 High-Lift Performance Camshaft

Transform your scooter's power band with the RDLN A9 Performance Camshaft. Designed specifically for the GY6 50cc (139QMB) platform, the A9 profile is the industry standard for increased performance. By increasing valve lift and extending duration, this camshaft allows your engine to breathe deeper at high RPMs, delivering a significant boost in mid-range torque and top-end speed.

The RDLN Engineering Edge

• Optimized Valve Timing: The A9 profile is engineered to provide a more aggressive lift than stock, ensuring maximum air/fuel intake for engines equipped with 72cc to 100cc Big Bore Kits.
• Premium Bearing Assembly: Pre-fitted with high-speed, low-friction steel bearings to ensure smooth rotation and long-term reliability under high-heat racing conditions.
• Forged Steel Alloy: CNC-machined from high-carbon steel alloy, preventing lobe wear and "pitting" over time.
• Drop-In Installation: Designed as a direct replacement for the stock camshaft; no machining of the head or valve train is required for standard 139QMB applications.

Fitment Guide

This camshaft is compatible with 139QMA / 139QMB engine heads found on nearly all 4-stroke 50cc Chinese scooters:

Don't see your engine listed? If the engine code includes "QM" or "FM", this product is compatible with your vehicle.

Technical Specifications

• Intake Lobe: 26.50mm ( ±0.05)
• Exhaust Lobe: 26.35mm ( ±0.05)
• Material: Hardened Steel Alloy
• Certification: ISO 9001
• Included: Complete Camshaft with pre-installed bearings

Tuning Tip: To fully realize the gains of the A9 camshaft, we recommend pairing it with a High-Flow Intake Manifold and slightly stiffer Valve Springs. Always re-adjust your valve lash to .004" (0.10mm) for both Intake and Exhaust after installation.

About RDLN: RDLN is a premier line of aftermarket performance upgrade systems and components for scooters. RDLN products are engineered to significantly improve the function, performance, and reliability of your vehicle with the ultimate goal being an optimal balance of price, power, and performance. RDLN’s extensive field-testing network ensures each product exceeds customer requirements and expectations every time. RDLN delivers full-throttle performance at uncompromised quality.

This product is intended for off-road use only.

This product is not intended for use on public roads or land.

This product is not legal for use in Californ

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