NCY Performance Camshaft 139QMB GY6 50cc

Description

Unlock the hidden power potential of your 4-stroke scooter with the NCY Performance Camshaft. Designed specifically for the GY6 139QMB engine platform, this high-lift cam profile increases valve duration and lift, allowing your engine to breathe deeper and rev higher. This is the recommended essential upgrade whenever you install a 72cc, 82cc, or 100cc big-bore cylinder kit to ensure your engine can fully utilize the increased displacement.

By optimizing the intake and exhaust timing, this camshaft shifts your power band upward, resulting in significantly improved acceleration and higher top-end performance. 

Product Features

• Optimized Lobe Geometry: Increased lift and duration profiles significantly improve volumetric efficiency compared to restrictive OEM stock cams.
• Precision-Machined Sprocket: Includes a factory-indexed 34-tooth timing sprocket for precise valve-to-piston synchronization.
• Hardened Steel Core: Constructed from high-strength, wear-resistant steel to withstand the sustained high-RPM heat and stress of modified performance builds.
• Plug-and-Play Fitment: Designed for drop-in installation into stock 139QMB cylinder heads (no machining required).

Technical Specifications

• Intake Lobe: 25.8mm x 21mm x 10.3mm
• Exhaust Lobe: 25.5mm x 21mm x 10.2mm
• Sprocket Teeth: 34
• Bearings: 2 TPI 16002C3 (18x32x8mm)
• SKU Reference: 1100-1250

Comprehensive Engine Fitment Matrix

This camshaft is a direct fit for 139QMB-based 50cc, 72cc, 82cc, and 100cc 4-stroke engines using the following factory designations:

Tuning Mechanic’s Advice & Safety Warning: When installing any high-performance camshaft alongside a big-bore kit, you must manually verify valve-to-piston clearance by rotating the crankshaft by hand before attempting a startup. If you do not have adequate clearance, you risk catastrophic engine failure. Additionally, ensure your valve lash (clearance) is set to manufacturer performance specifications (typically 0.003″–0.004″ for intake/exhaust on modified engines) immediately upon installation.