{"product_id":"gy6-50cc-139qmb-cylinder-head-emissions","title":"GY6 50cc (139QMB) Cylinder Head - Emissions","description":"\u003ch2\u003eGY6 50cc Cylinder Head Built for 139QMB Engines\u003c\/h2\u003e\u003cp\u003eThis GY6 50cc Cylinder Head suits 50cc 4-stroke QMB139 engines and uses a PAIR emissions setup, short for Pulsed Secondary Air Injection System. The system pushes air into the exhaust stream to cut down on hydrocarbon (HC) and carbon monoxide (CO) output. It's one of the \u003ca href=\"\/collections\/gy6-50cc-parts\"\u003eGY6 50cc scooter parts\u003c\/a\u003e that helps your engine run cleaner and more efficiently.\u003c\/p\u003e\u003ch3\u003eEmissions Control System\u003c\/h3\u003e\u003cp\u003eThis head includes the PAIR system, which helps limit harmful exhaust output from your scooter. Adding fresh air to the exhaust supports more complete combustion and helps meet emissions standards. It's a useful feature for riders who want to lower their environmental footprint without giving up engine performance.\u003c\/p\u003e\u003ch3\u003eSpecifications and Dimensions\u003c\/h3\u003e\u003cp\u003eThe GY6 50cc Cylinder Head is machined to exact measurements so it lines up properly with your engine. It has a 39mm bore, a 17mm intake port diameter, and an 18mm exhaust port diameter. Getting these dimensions right matters for keeping the air-fuel mixture balanced, which directly affects how the engine performs.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSize:\u003c\/strong\u003e 39mm Bore\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIntake Port Diameter:\u003c\/strong\u003e 17mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExhaust Port Diameter:\u003c\/strong\u003e 18mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEmission Control System:\u003c\/strong\u003e Pulsed Secondary Air Injection (PAIR)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Universal GY6 50cc QMB139 4-stroke engines with PAIR emissions cylinder head\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cp\u003eFits:\u003c\/p\u003e\u003cul\u003e\u003cli\u003eUniversal QMB139 50cc\/49cc 4-stroke engines (PAIR emissions style, 39mm bore)\u003c\/li\u003e\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eHow to choose:\u003c\/strong\u003e Confirm your engine has a 39mm bore and the QMB139 designation, and verify it uses a PAIR emissions system before ordering.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eShop more:\u003c\/strong\u003e \u003ca href=\"\/collections\/gy6-50cc-parts\"\u003eGY6 50cc Scooter Parts (139QMB)\u003c\/a\u003e · \u003ca href=\"\/collections\/gy6-scooter-parts\"\u003eGY6 Scooter Parts\u003c\/a\u003e · \u003ca href=\"\/collections\/scooter-cylinder-heads\"\u003eScooter Cylinder Heads \u0026amp; Valves\u003c\/a\u003e · \u003ca href=\"\/collections\/scooter-parts\"\u003eScooter Parts\u003c\/a\u003e\u003c\/p\u003e","brand":"Trend Times Toy Stores","offers":[{"title":"Default Title","offer_id":51134474518585,"sku":"TT-16007","price":43.98,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0665\/3358\/9049\/files\/gy6-50cc-139qmb-cylinder-head-emissions-1.jpg?v=1794344415","url":"https:\/\/www.trendtimes.com\/products\/gy6-50cc-139qmb-cylinder-head-emissions","provider":"Trend Times Toy Stores","version":"1.0","type":"link"}