{"product_id":"ncy-performance-cylinder-head-50mm-81cc-alloy-qmb139-1100-1239","title":"NCY 139QMB Performance Cylinder Head 81cc 50mm","description":"\u003cp\u003eThe NCY 81cc Aluminum Performance Cylinder Head is a direct upgrade for 50cc 139QMB-based engines. Pair it with NCY's \u003ca href=\"https:\/\/www.scooterworks.com\/products\/ncy-cylinder-kit-81cc-iron-50mm-qmb139?variant=46756515414296\" title=\"NCY 81cc Cylinder Kit\"\u003e81cc Cylinder Kit\u003c\/a\u003e to push past stock displacement and gain the power needed for city traffic and hills.\u003c\/p\u003e\u003cp\u003eMade in Taiwan. ISO 9001 certified. NCY has been the aftermarket performance leader for popular scooter platforms since 1997.\u003c\/p\u003e\u003ch2\u003eKey Features\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e81cc alloy performance cylinder head for 139QMB \/ GY6 50cc engines\u003c\/li\u003e\n\u003cli\u003e50mm stud spacing — direct fit for QMB\/QMA engine families\u003c\/li\u003e\n\u003cli\u003e64mm valve stem height — requires \u003ca href=\"https:\/\/www.scooterworks.com\/products\/rocker-arm-assembly-type-1-64mm-qmb139\" title=\"64mm rocker arm assembly\"\u003e64mm rocker arm assembly\u003c\/a\u003e (not included)\u003c\/li\u003e\n\u003cli\u003e6mm intake and exhaust threads\u003c\/li\u003e\n\u003cli\u003eISO 9001 certified manufacturing\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eSpecifications\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eStud Spacing: 50mm\u003c\/li\u003e\n\u003cli\u003eHead Height: 60mm\u003c\/li\u003e\n\u003cli\u003eIntake Port: 24mm\u003c\/li\u003e\n\u003cli\u003eExhaust Port: 22mm\u003c\/li\u003e\n\u003cli\u003eIntake Valve: 21.5 x 64mm\u003c\/li\u003e\n\u003cli\u003eExhaust Valve: 19 x 64mm\u003c\/li\u003e\n\u003cli\u003eValve Stem Diameter: 5mm\u003c\/li\u003e\n\u003cli\u003eValve Stem Length: 64mm\u003c\/li\u003e\n\u003cli\u003eIntake Threads: 6mm\u003c\/li\u003e\n\u003cli\u003eExhaust Threads: 6mm\u003c\/li\u003e\n\u003cli\u003eHead Height w\/ Intake Valves: 66.1–67.3mm\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eNote:\u003c\/strong\u003e Most stock 139QMB heads use 69mm valves and a 69mm rocker arm. This head uses 64mm valves and requires a 64mm rocker arm. Verify your stock valve stem height before ordering.\u003c\/p\u003e\u003ch2\u003eCompatibility\u003c\/h2\u003e\u003cp\u003eFits 139QMB-based 50cc \/ 80cc engines with the following engine codes:\u003c\/p\u003e\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\u003cth\u003eEngine Codes\u003c\/th\u003e\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\u003ctr\u003e\u003ctd\u003e139QMA, 139QMB, 1P39QMB, 1P39QMA-2, YN139QMB, JJ1P39QMB, 139FMA-2, BD1P39QMB, BN139QMB, 147QMD, Other QMA\/QMB models\u003c\/td\u003e\u003c\/tr\u003e\u003c\/tbody\u003e\n\u003c\/table\u003e\u003cp\u003eIf your engine code includes \"QM\" or \"FM\" and your valve height and rocker arm are 64mm, this head is compatible. Visit our \u003ca href=\"https:\/\/www.scooterworks.com\/collections\/shop-by-diagrams-1\" title=\"Shop by Diagrams\"\u003eShop by Diagrams\u003c\/a\u003e page to confirm fitment.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003ePerformance upgrades are considered racing parts and are not covered under warranty.\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThis product is intended for off-road use only. Not legal for use in California on pollution-controlled vehicles. Check local laws before installing.\u003c\/p\u003e\u003cp\u003e\u003ca href=\"http:\/\/www.p65warnings.ca.gov\"\u003eCalifornia Prop 65 Warning: www.p65warnings.ca.gov\u003c\/a\u003e\u003c\/p\u003e","brand":"NCY","offers":[{"title":"Default Title","offer_id":48111855337659,"sku":"1100-1239","price":168.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0719\/1340\/6651\/files\/1100-1239_1ec7c4bb-e27f-496a-b8f3-7cd1c594c333.jpg?v=1784296846","url":"https:\/\/thriftyscooters.com\/products\/ncy-performance-cylinder-head-50mm-81cc-alloy-qmb139-1100-1239","provider":"Thrifty Scooters","version":"1.0","type":"link"}