NCY High-RPM Racing Valve Set - 28/23mm for GY6

NCY Performance Racing Valves deliver a noticeable improvement in idle quality and high-end pull on GY6 125cc, 150cc, and 171cc engines. Precision-lapped seats ensure a perfect 360° seal, eliminating compression loss and erratic idling common with soft factory valves that stretch or leak under high stress. These are also the OEM replacement valves for the NCY Big Valve High-Flow Cylinder Head (SKU 1100-1254) . Made in Taiwan. SKU: 1100-1257. Key Features Precision lapped seats — perfect 360° seal eliminates compression loss and erratic idle High-heat durability resists mushrooming and carbon buildup vs. OEM valves Optimized flow profile for high-flow heads at 10,000+ RPM IN: 27.8mm / EX: 22.9mm — fits GY6 125cc, 150cc, and 171cc BBK applications Premium NCY manufacturing for superior balance and longevity Specifications Intake Valve (IN): 27.8mm OD | 65.75mm height | 5.0mm stem Exhaust Valve (EX): 22.9mm OD | 65.3mm height | 5.0mm stem MPN: 665C13GY628LL SKU: 1100-1257 Origin: Made in Taiwan Compatibility Application Engine Codes / Models Genuine Scooter Co. Buddy 125, Buddy 150, Buddy 170i, Blur 150 Standard GY6 Codes 157QMJ, 152QMI, 161QMK, 1P61QMK, YN1P57QMJ Big Bore Kits 58.5mm (155cc), 61mm (171cc), 62mm, 63mm BBKs Tech Tip: Pair with NCY Performance Valve Springs rated for 11,000 RPM. Always lap new valves into the head with fine-grit grinding compound to ensure a gas-tight seal before final assembly. This product is intended for off-road use only. 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. California Prop 65 Warning: www.p65warnings.ca.gov