{"product_id":"gy6-50cc-139qmb-stroker-crankshaft","title":"GY6 50cc (139QMB) Stroker Crankshaft","description":"\u003ch2\u003eGY6 50cc Stroker Crankshaft for QMB139 Engines\u003c\/h2\u003e\u003cp\u003eThe 44mm Stroker Crankshaft Assembly is designed specifically for 50cc 4-stroke QMB139 engines, making it a reliable component for scooter enthusiasts. This crankshaft is engineered to improve performance and is ideal for those looking to replace worn parts within their engine. It is one of the \u003ca href=\"\/collections\/gy6-50cc-parts\"\u003eGY6 50cc scooter parts\u003c\/a\u003e that can significantly affect engine output and efficiency. Designed for straightforward installation, this crankshaft is a key part for maintaining proper engine function.\u003c\/p\u003e\u003ch3\u003eConstruction and Specifications\u003c\/h3\u003e\u003cp\u003eThis crankshaft assembly features precise engineering to ensure compatibility and performance. With an overall length of 247mm, it is built to fit comfortably within the engine. The tapered side has a thread size of M10x1.25, while the spline side is M12x1.25. The bearings have outer diameters of 42mm on the tapered side and 47mm on the spline side, facilitating smooth operation.\u003c\/p\u003e\u003ch3\u003eWhen to Consider Replacement\u003c\/h3\u003e\u003cp\u003eReplacing the crankshaft may be necessary when experiencing decreased engine performance or unusual vibrations during operation. If you're noticing issues with the oil pump drive gear, which has 16 teeth and is compatible with a 33t oil pump, it could also indicate the need for a new crankshaft. Regular maintenance checks can help identify when it's time for a replacement.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSize:\u003c\/strong\u003e 44mm Stroker\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOverall Length:\u003c\/strong\u003e 247mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread Size (Tapered Side):\u003c\/strong\u003e M10x1.25\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread Size (Spline Side):\u003c\/strong\u003e M12x1.25\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBearing Outer Diameter (Tapered Side):\u003c\/strong\u003e 42mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBearing Outer Diameter (Spline Side):\u003c\/strong\u003e 47mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNumber of Splines:\u003c\/strong\u003e 26\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConnecting Rod Inner Diameter:\u003c\/strong\u003e 13mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNumber of Teeth (Oil Pump Drive Gear):\u003c\/strong\u003e 16\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cp\u003eThis crankshaft is compatible with QMB139 50cc\/49cc engines.\u003c\/p\u003e\u003cul\u003e\u003cli\u003eGY6 50cc scooters\u003c\/li\u003e\u003c\/ul\u003e\u003cp\u003eNot sure it fits? Contact us with your scooter's make, model and year and we'll confirm the fit before you order.\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-engines\"\u003eScooter Engines \u0026amp; Engine Parts\u003c\/a\u003e · \u003ca href=\"\/collections\/scooter-parts\"\u003eScooter Parts\u003c\/a\u003e\u003c\/p\u003e","brand":"Magic Cars","offers":[{"title":"Default Title","offer_id":52795173470439,"sku":"25-902647","price":186.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/2245\/9711\/files\/gy6-50cc-139qmb-stroker-crankshaft-1.webp?v=1791584174","url":"https:\/\/www.magiccars.com\/products\/gy6-50cc-139qmb-stroker-crankshaft","provider":"MagicCars","version":"1.0","type":"link"}