{"product_id":"naraku-heavy-duty-crankshaft-16-tooth-139qmb-engines","title":"Naraku Heavy Duty Crankshaft 16 Tooth | 139QMB Engines","description":"\u003cp\u003eThe \u003cstrong\u003eNaraku Heavy Duty Crankshaft\u003c\/strong\u003e (SKU 137-78, MPN NK100.81) is a premium OEM-quality replacement for 50cc 4-stroke QMB139 engines. Shown with the Naraku retail box — built to Japanese and Taiwanese OEM standards with a fully machined crankshaft assembly: central flywheel\/crankpin with pre-pressed heavy-duty bearings, forged steel connecting rod with wrist pin eye, dual-end main shafts with splined PTO end and threaded timing\/stator end, and a visible 16-tooth oil pump drive gear. Matches original crank dimensions for a direct drop-in fit in standard and Big Bore builds. Verify your engine uses a 16-tooth oil pump drive gear before ordering.\u003c\/p\u003e\u003ch2\u003eFeatures\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eOEM-quality construction to Japanese and Taiwanese standards\u003c\/li\u003e\n\u003cli\u003eHeavy-duty bearings pre-pressed for longer service life\u003c\/li\u003e\n\u003cli\u003e16-tooth oil pump drive gear\u003c\/li\u003e\n\u003cli\u003eDirect OEM-dimension replacement — fits standard and Big Bore builds\u003c\/li\u003e\n\u003cli\u003ePre-assembled and ready to install\u003c\/li\u003e\n\u003cli\u003eMade in Taiwan by Naraku (MPN: NK100.81)\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eSpecifications\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSKU:\u003c\/strong\u003e 137-78\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMPN:\u003c\/strong\u003e NK100.81\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Naraku (Taiwan)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEngine Compatibility:\u003c\/strong\u003e QMB139 \/ 139QMB 49cc \/ 50cc 4-stroke horizontal\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOil Pump Drive Gear:\u003c\/strong\u003e 16 tooth\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIncludes:\u003c\/strong\u003e Pre-pressed heavy-duty bearings\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDimensions (packaged):\u003c\/strong\u003e 11\" L x 5\" W x 4\" H\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eModel Fitment\u003c\/h2\u003e\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eEngine\u003c\/th\u003e\n\u003cth\u003eDisplacement\u003c\/th\u003e\n\u003cth\u003eType\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\u003ctr\u003e\n\u003ctd\u003e139QMB \/ QMB139\u003c\/td\u003e\n\u003ctd\u003e49cc \/ 50cc\u003c\/td\u003e\n\u003ctd\u003e4-stroke horizontal\u003c\/td\u003e\n\u003c\/tr\u003e\u003c\/tbody\u003e\n\u003c\/table\u003e\u003cp\u003e\u003cstrong\u003eNote:\u003c\/strong\u003e Confirm your engine uses a 16-tooth oil pump drive gear before ordering.\u003c\/p\u003e\u003cp\u003eIntended for off-road and racing use only. Not intended for use on public roads.\u003c\/p\u003e\u003cp\u003e \u003c\/p\u003e\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e","brand":"Naraku","offers":[{"title":"Default Title","offer_id":67964676604225,"sku":"137-78","price":200.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1011\/7785\/2225\/files\/az-p012-15058-0-137-78.main.01.default.jpg?v=1792558778","url":"https:\/\/azscooterparts.com\/products\/naraku-heavy-duty-crankshaft-16-tooth-139qmb-engines","provider":"AZScooterParts","version":"1.0","type":"link"}