{"product_id":"gy6-57mm-cylinder-head-pair-type","title":"GY6 57mm Cylinder Head - PAIR Type","description":"\u003ch2\u003e57mm Cylinder Head for GY6 150cc Engines\u003c\/h2\u003e\u003cp\u003eThis 57mm PAIR cylinder head is made for GY6 150cc engines and works as a full replacement when you are rebuilding your motor. It arrives fully assembled with the parts needed to swap out a damaged head. Using it means you can bring your engine back to working order without building everything from scratch. Thanks to its complete assembly and fit with the engine layout, it is one of the simpler \u003ca href=\"\/collections\/gy6-scooter-parts\"\u003eGY6 scooter parts\u003c\/a\u003e to install.\u003c\/p\u003e\u003ch3\u003eReady-to-Fit Valve Setup\u003c\/h3\u003e\u003cp\u003eThe head ships with its valve assembly already built up, so the intake and exhaust valves and their springs are in place. That keeps the install quicker and less involved during a rebuild. It is a useful option for anyone aiming to get more out of a GY6 engine.\u003c\/p\u003e\u003ch3\u003ePAIR Emissions Compatibility\u003c\/h3\u003e\u003cp\u003eThe design accommodates the Pulsed Secondary Air Injection (PAIR) system, which cuts harmful emissions by feeding air into the exhaust stream. This helps with emissions compliance while keeping the engine running efficiently. On off-road machines without this system, the PAIR port can be blanked off during installation if needed.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eType:\u003c\/strong\u003e Complete emissions-type cylinder head\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEngine Platform:\u003c\/strong\u003e GY6-A four-stroke\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrimary Application:\u003c\/strong\u003e 150cc QMJ157\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBore Size:\u003c\/strong\u003e 57 mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOverall Height:\u003c\/strong\u003e 60.5 mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHead-Stud Spacing:\u003c\/strong\u003e 54 mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDiagonal Head-Stud Spacing:\u003c\/strong\u003e 76.5 mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDiagonal Valve-Cover Bolt Spacing:\u003c\/strong\u003e 144 mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIntake Valve Diameter:\u003c\/strong\u003e 29 mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExhaust Valve Diameter:\u003c\/strong\u003e 23.5 mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEmissions Feature:\u003c\/strong\u003e PAIR secondary-air system\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIncluded:\u003c\/strong\u003e Installed valves and springs; intake and exhaust studs\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e GY6-A 150cc four-stroke engines (QMJ157 \/ 157QMJ) with 57 mm bore and PAIR provision\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cp\u003eFits:\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eGY6-A 150cc QMJ157 \/ 157QMJ (57 mm bore, 54 mm head-stud spacing, PAIR secondary-air provision)\u003c\/li\u003e\n\u003cli\u003eGY6 QMI\/QMJ 152\/157 applications (match bore, stud spacing and valve-cover bolt layout)\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eHow to choose:\u003c\/strong\u003e Check that the engine code and dimensions line up with your current head: 57 mm bore, 54 mm head-stud spacing, 60.5 mm overall height.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eShop more:\u003c\/strong\u003e \u003ca href=\"\/collections\/gy6-scooter-parts\"\u003eGY6 Scooter Parts\u003c\/a\u003e · \u003ca href=\"\/collections\/chinese-scooter-parts\"\u003eChinese 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":51135679889465,"sku":"TT-16319","price":75.98,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0665\/3358\/9049\/files\/gy6-57mm-cylinder-head-pair-type-1.jpg?v=1794349529","url":"https:\/\/www.trendtimes.com\/products\/gy6-57mm-cylinder-head-pair-type","provider":"Trend Times Toy Stores","version":"1.0","type":"link"}