{"product_id":"47mm-gy6-50cc-139qmb-complete-non-emissions-cylinder-head","title":"47mm GY6 50cc (139QMB) Complete Non Emissions Cylinder Head","description":"\u003ch2\u003eFull Cylinder Head Assembly for 47mm GY6 50cc Engines\u003c\/h2\u003e\u003cp\u003eThis non-emissions cylinder head is built for the 50cc QMB139 four-stroke engine and includes the main parts needed for better performance. Its 47mm size makes it a good match for anyone planning to move up to a 72cc big bore kit. You can also browse our \u003ca href=\"\/collections\/gy6-50cc-parts\"\u003eGY6 50cc scooter parts\u003c\/a\u003e when you are upgrading engine output or swapping out worn components.\u003c\/p\u003e\u003ch3\u003eSpecifications and Design\u003c\/h3\u003e\u003cp\u003eThe head uses 64mm valves to support better airflow and combustion. Overall height is 59.5mm. The intake port measures 17mm across and the exhaust port 18mm. Intake bolt holes are spaced 44.5mm apart, and exhaust bolt holes are spaced 50mm apart.\u003c\/p\u003e\u003ch3\u003eInstallation and Replacement\u003c\/h3\u003e\u003cp\u003eThis head suits specific performance upgrades and modifications. Before fitting it, confirm all connections are tight and that it lines up correctly with the rest of your engine. Inspecting the head on a regular basis helps keep the engine running well and can catch problems early.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSize:\u003c\/strong\u003e 47mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eValve Length:\u003c\/strong\u003e 64mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOverall Height:\u003c\/strong\u003e 59.5mm\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\u003eIntake Bolt Hole Spacing:\u003c\/strong\u003e 44.5mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExhaust Bolt Hole Spacing:\u003c\/strong\u003e 50mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e GY6 50cc (139QMB) 4-stroke engines with 47mm bore; for use with 72cc big bore kit\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cp\u003eCompatible with:\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eGY6 50cc QMB139 4-stroke engines (non emissions, 47mm bore)\u003c\/li\u003e\n\u003cli\u003eGY6 50cc QMB139 engines with 72cc big bore kit\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eHow to choose:\u003c\/strong\u003e Check that your engine bore is 47mm and the model code is QMB139 before you order. If you are running a 72cc big bore setup, this is the head made for that build.\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":51134662574137,"sku":"TT-16221","price":54.98,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0665\/3358\/9049\/files\/47mm-gy6-50cc-139qmb-complete-non-emissions-cylinder-head-1.jpg?v=1794346420","url":"https:\/\/www.trendtimes.com\/products\/47mm-gy6-50cc-139qmb-complete-non-emissions-cylinder-head","provider":"Trend Times Toy Stores","version":"1.0","type":"link"}