{"product_id":"ncy-performance-camshaft-139qmb-gy6-50cc","title":"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: Engine Series Code Compatible 139QMB \/ GY6 50cc Variants Common Codes 139QMA, 139QMB, 1P39QMB, 1P39QMA-2, YN139QMB, JJ139QMB, 139FMA-2, BD1P39QMB, BN139QMB, 147QMD Tuning Mechanic's Advice \u0026amp; 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. California Prop 65 Warning 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 California on pollution-controlled vehicles. Check local laws before installing. *Performance upgrades are considered racing parts and are not covered by warranty.","brand":"ncy","offers":[{"title":"Default Title","offer_id":48045175439547,"sku":"1100-1250","price":72.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0719\/1340\/6651\/files\/1100-1250_1d7d662d-80fe-4749-b173-b03d5c034eb9.jpg?v=1783053218","url":"https:\/\/thriftyscooters.com\/products\/ncy-performance-camshaft-139qmb-gy6-50cc","provider":"Thrifty Scooters","version":"1.0","type":"link"}