{"product_id":"hammerhead-61mm-171cc-engine-rebuild-kit-with-cylinder-and-top-end-for-150cc-gy6","title":"Hammerhead Big Bore 61mm (171cc) Engine Rebuild Kit with Cylinder and Top End for 150cc, GY6","description":"\u003cp\u003eHammerhead Big Bore 61mm \/ 171cc  Engine Rebuild Kit with complete head assembly and top end kit.  The \u003cstrong\u003eHammerhead 61mm Big Bore Kit\u003c\/strong\u003e is the only 171cc upgrade available in the U.S. designed to fit without machining your engine cases.  Featuring a specialized \u003cstrong\u003e62.9mm outer skirt\u003c\/strong\u003e, this aluminum cylinder drops directly into standard GY6 150cc engines. It is the best bang for the buck for riders demanding a massive jump in torque and acceleration without the need for professional machine shop services.\u003cbr\u003e\u003cbr\u003e\u003cspan\u003e\u003cstrong\u003eHammerhead Big Bore 61mm \/ 171cc Engine REBUILD Kit includes:\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eComplete head assy with valves, everything assembled ready to bolt on and go\u003c\/li\u003e\n\u003cli\u003ePiston cylinder kit\u003c\/li\u003e\n\u003cli\u003ecylinder\u003c\/li\u003e\n\u003cli\u003episton \u003c\/li\u003e\n\u003cli\u003erings\u003c\/li\u003e\n\u003cli\u003e2-clips\u003c\/li\u003e\n\u003cli\u003epin\u003c\/li\u003e\n\u003cli\u003ecomplete set of gaskets\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eThe \u003cspan\u003eHammerHead \u003c\/span\u003e\u003cspan\u003ePerformance \u003c\/span\u003eAdvantage\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue Bolt-On Engineering:\u003c\/strong\u003e Slim-skirt design eliminates the need to \"split the cases\" or grind the engine block for clearance.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAdvanced Thermal Cooling:\u003c\/strong\u003e All-aluminum construction dissipates heat significantly faster than stock cast-iron cylinders, preventing power fade during long-distance riding.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHigh-RPM Piston:\u003c\/strong\u003e Includes a specialized \"short-skirt\" racing piston to reduce reciprocating mass, allowing for faster revving and higher top-end potential.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eComprehensive Kit:\u003c\/strong\u003e Includes cylinder, piston, rings, wrist pin, clips, and performance gaskets.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eTechnical Specifications\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDisplacement:\u003c\/strong\u003e 171.3cc (61mm Bore)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOuter Skirt Diameter:\u003c\/strong\u003e 62.99mm (Direct Fit)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e High-Grade Aluminum\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eKit Includes:\u003c\/strong\u003e Cylinder, Piston, Rings, Wrist Pin, Clips, and Performance Gaskets.\u003c\/li\u003e\n\u003cli\u003ePLEASE NOTE:  Usually requires a bigger main jet (125 - 130) for optimal performance. \n\u003cp\u003eThis product is intended for off-road use only.\u003c\/p\u003e\n\u003cp\u003eThis product is not intended for use on public roads or land.\u003c\/p\u003e\n\u003cp\u003eThis product is not legal for use in California on pollution-controlled vehicles. Check local laws before installing.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"HammerHead Performance","offers":[{"title":"Default Title","offer_id":53483574886765,"sku":"61mmREBUILDKIT171cc_hhpPS","price":299.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1004\/2710\/4621\/files\/big_bore_kit.jpg?v=1782374608","url":"https:\/\/hammerheadperformance.com\/products\/hammerhead-61mm-171cc-engine-rebuild-kit-with-cylinder-and-top-end-for-150cc-gy6","provider":"HammerHead Performance","version":"1.0","type":"link"}