{"product_id":"naraku-qmb139-52-4mm-performance-cylinder-head-kit-137-4","title":"Naraku QMB139 52.4mm Performance Cylinder \u0026 Head Kit","description":"Naraku 50cc QMB139 4-stroke 52.4mm, Racing Big Bore Cylinder and Head Kit. Kit includes cylinder, piston, rings, piston pin, cir clips, cylinder head, head gasket, and base gasket.\u003cbr\u003e\u003cbr\u003eWhen used in conjunction with a stock stroke of 41.4mm the total displacement comes out to 89.3cc! When used with a 44mm stroker crank, total displacement measures 94.9cc!\u003cbr\u003e \u003cbr\u003ePlease see our Warranty \u0026amp; Returns Policy.\u003cbr\u003e\u003cbr\u003e\u003cp style=\"margin: 0in 0in 0pt; font-family: Tahoma; color: rgb(0, 0, 0); font-size: 12pt; --darkreader-inline-color:#e8e6e3;\" class=\"MsoNormal\" data-darkreader-inline-color=\"\"\u003e\u003cspan style=\"font-family: Tahoma; color: black; font-size: 10pt; --darkreader-inline-color:#e8e6e3;\" data-darkreader-inline-color=\"\"\u003e\u003cfont color=\"#000000\" size=\"2\" data-darkreader-inline-color=\"\" style=\"--darkreader-inline-color:#e8e6e3;\"\u003e\u003cfont color=\"#0000ff\" size=\"3\" data-darkreader-inline-color=\"\" style=\"--darkreader-inline-color:#337dff;\"\u003e\u003cfont color=\"#ff0000\" data-darkreader-inline-color=\"\" style=\"--darkreader-inline-color:#ff3333;\"\u003e\u003cspan style=\"font-family: tahoma;\"\u003ePlease note: replaces Cylinder Heads with 64mm Valves (Short Valve Style). Please see Related Items if you need 64mm valves. \u003c\/span\u003eYou may need to modify your engine case to accommodate the larger cylinder.\u003cbr\u003e\u003c\/font\u003e\u003c\/font\u003e\u003c\/font\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cul\u003e \n\n\u003cli\u003eUpgrades to 89.3cc  \n\n\u003c\/li\u003e\n\u003cli\u003eCylinder Bore: 52.4mm  \n\n\u003c\/li\u003e\n\u003cli\u003eCylinder Sleeve Outer Diameter: 54.4mm   \n\n\u003c\/li\u003e\n\u003cli\u003eWrist Pin Diameter: 13mm  \n\n\u003c\/li\u003e\n\u003cli\u003eTotal Piston Height: 36.3mm  \n\n\u003c\/li\u003e\n\u003cli\u003eCompression Height (from center of wrist pin hole to top edge of piston): 20mm\u003c\/li\u003e\n\u003cli\u003eNon-emissions style head\u003c\/li\u003e\n\u003cli\u003eIntake valve: 23mm\u003c\/li\u003e\n\u003cli\u003eExhaust valve: 20mm\u003c\/li\u003e\n\u003cli\u003eIntake Port Diameter: 20.8mm\u003c\/li\u003e\n\u003cli\u003eExhaust Port Diameter: 18.7mm\u003c\/li\u003e\n\u003cli\u003eUses Short 64mm Valve Stems\u003c\/li\u003e\n\u003c\/ul\u003eQMB139 50cc\/49cc , Various unlisted makes\/models\u003cp\u003e \u003c\/p\u003e\u003ch3 style=\"color:#983D3C;\"\u003eThis product is not intended for use on public roads or land.\u003c\/h3\u003e","brand":"Naraku","offers":[{"title":"Default Title","offer_id":49985985216792,"sku":"137-4","price":300.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0782\/1728\/1816\/files\/450236.jpg?v=1744827319","url":"https:\/\/www.scooterworks.com\/products\/naraku-qmb139-52-4mm-performance-cylinder-head-kit-137-4","provider":"Scooterworks USA, LLC","version":"1.0","type":"link"}