{"product_id":"naraku-47mm-performance-cylinder-kit","title":"Naraku 72cc Big Bore Cylinder Kit 47mm - QMB139 \/ 139QMB","description":"\u003cp\u003eGive your 50cc four-stroke scooter a significant boost of power with the \u003cstrong\u003eNaraku 47mm 72cc Big Bore Cylinder Kit\u003c\/strong\u003e for compatible QMB139 \/ 139QMB 49cc and 50cc engines. The larger bore increases displacement to approximately 72cc with the stock 41.4mm stroke, giving you a solid starting point for a more powerful engine setup. The cylinder, piston hardware, and replacement gaskets come together in one kit, so you can spend less time gathering parts and more time on the build.\u003c\/p\u003e\u003ch2\u003eFeatures\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e72cc Upgrade:\u003c\/strong\u003e 47mm bore produces approximately 72cc when paired with the stock 41.4mm stroke.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDrop-In Cylinder Design:\u003c\/strong\u003e No crankcase modifications required on compatible engines.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMatched Piston Components:\u003c\/strong\u003e Includes piston, rings, wrist pin and circlips.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGaskets Included:\u003c\/strong\u003e Head, base, exhaust and cam-chain tensioner gaskets support cylinder installation.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eSpecifications\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Naraku\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart number:\u003c\/strong\u003e 137-13\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer reference:\u003c\/strong\u003e NK100.47\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCylinder bore:\u003c\/strong\u003e 47mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDisplacement:\u003c\/strong\u003e Approximately 72cc with a 41.4mm stroke\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCylinder sleeve outer diameter:\u003c\/strong\u003e 53.1mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWrist pin diameter:\u003c\/strong\u003e 13mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTotal piston height:\u003c\/strong\u003e 34.1mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEngine type:\u003c\/strong\u003e QMB139 \/ 139QMB 49cc–50cc four-stroke\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eWhat's Included\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eCylinder\u003c\/li\u003e\n\u003cli\u003ePiston and rings\u003c\/li\u003e\n\u003cli\u003ePiston wrist pin and circlips\u003c\/li\u003e\n\u003cli\u003eHead gasket\u003c\/li\u003e\n\u003cli\u003eBase gasket\u003c\/li\u003e\n\u003cli\u003eExhaust gasket\u003c\/li\u003e\n\u003cli\u003eCam-chain tensioner gasket\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eModel Fitment\u003c\/h2\u003e\u003cp\u003eFor compatible Chinese-market QMB139 \/ 139QMB 49cc and 50cc four-stroke scooter engines, including various unlisted makes and models. Compare the original cylinder mounting layout, 53.1mm sleeve clearance, 13mm wrist pin, and piston dimensions before installation. Engine code alone does not guarantee every engine variant matches.\u003c\/p\u003e\u003cp\u003eCheck cylinder-head compatibility, piston-to-valve clearance, and fueling setup as part of the build; additional tuning or components may be needed for your configuration. \u003c\/p\u003e\u003cp\u003eThis product is intended for off-road use only. This product is not intended for use on public roads or land.\u003c\/p\u003e","brand":"Naraku","offers":[{"title":"Default Title","offer_id":67964507160897,"sku":"137-13","price":125.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1011\/7785\/2225\/files\/Naraku_piston_0857226d-b60d-4ab0-96e1-2f58ff85d5da.jpg?v=1792793720","url":"https:\/\/azscooterparts.com\/products\/naraku-47mm-performance-cylinder-kit","provider":"AZScooterParts","version":"1.0","type":"link"}