{"product_id":"keith-black-pistons-dome-top-pistons-kb305-040-for-big-twin-1984-1999","title":"Keith Black Pistons Dome Top Pistons KB305.040 for Big Twin 1984-1999","description":"\u003cp style=\"margin:1em 0\"\u003eUpgrade your Harley-Davidson engine performance with Keith Black Pistons hypereutectic dome top pistons. Engineered specifically for Evolution Big Twin models, these pistons are manufactured from a high-silicon hypereutectic aluminum alloy designed to withstand the high thermal demands of air-cooled engines while maintaining minimal thermal expansion.\u003c\/p\u003e\u003cp style=\"margin:1em 0\"\u003eThis low expansion rate allows for tighter piston-to-cylinder operating clearances, ensuring superior ring seal, reduced noise, and extended service life. Delivering a 9.6:1 compression ratio with standard 80cc combustion chambers, this complete kit includes pistons, rings, wrist pins, and clips for a full engine refresh.\u003c\/p\u003e\n\u003ch3 style=\"margin:1.25em 0 0.5em\"\u003eKey Features\u003c\/h3\u003e\n\u003ctable class=\"pu-table\" style=\"width:100%;border-collapse:separate;border-spacing:0;border:0;box-shadow:none;outline:none;background:none;table-layout:fixed;margin:0 0 1em\"\u003e\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:0;padding:0.4em 0.75em 0.4em 0;opacity:0.65;vertical-align:top;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003eBrand\u003c\/td\u003e\n\u003ctd style=\"border:0;padding:0.4em 0;vertical-align:top;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003eKeith Black Pistons\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:0;padding:0.4em 0.75em 0.4em 0;opacity:0.65;vertical-align:top;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003eManufacturer Part Number (MPN)\u003c\/td\u003e\n\u003ctd style=\"border:0;padding:0.4em 0;vertical-align:top;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003eKB305.040\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:0;padding:0.4em 0.75em 0.4em 0;opacity:0.65;vertical-align:top;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003eProduct Type\u003c\/td\u003e\n\u003ctd style=\"border:0;padding:0.4em 0;vertical-align:top;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003eDome Top Pistons\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:0;padding:0.4em 0.75em 0.4em 0;opacity:0.65;vertical-align:top;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003eMaterial\u003c\/td\u003e\n\u003ctd style=\"border:0;padding:0.4em 0;vertical-align:top;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003eHypereutectic Alloy (16% Silicon)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:0;padding:0.4em 0.75em 0.4em 0;opacity:0.65;vertical-align:top;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003eBore Size\u003c\/td\u003e\n\u003ctd style=\"border:0;padding:0.4em 0;vertical-align:top;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003e89.9 mm (3.538 in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:0;padding:0.4em 0.75em 0.4em 0;opacity:0.65;vertical-align:top;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003eStroke\u003c\/td\u003e\n\u003ctd style=\"border:0;padding:0.4em 0;vertical-align:top;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003e108 mm (4.250 in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:0;padding:0.4em 0.75em 0.4em 0;opacity:0.65;vertical-align:top;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003eCompression Ratio\u003c\/td\u003e\n\u003ctd style=\"border:0;padding:0.4em 0;vertical-align:top;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003e9.6:1 (with 80cc Head Chamber Volume)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:0;padding:0.4em 0.75em 0.4em 0;opacity:0.65;vertical-align:top;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003ePiston Oversize\u003c\/td\u003e\n\u003ctd style=\"border:0;padding:0.4em 0;vertical-align:top;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003e+0.040 in\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:0;padding:0.4em 0.75em 0.4em 0;opacity:0.65;vertical-align:top;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003eEngine Type\u003c\/td\u003e\n\u003ctd style=\"border:0;padding:0.4em 0;vertical-align:top;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003eEvolution Big Twin\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:0;padding:0.4em 0.75em 0.4em 0;opacity:0.65;vertical-align:top\"\u003eWeight\u003c\/td\u003e\n\u003ctd style=\"border:0;padding:0.4em 0;vertical-align:top\"\u003e1.4 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e\n\u003ch3 style=\"margin:1.25em 0 0.5em\"\u003eHighlights\u003c\/h3\u003e\n\u003cul style=\"margin:1em 0\"\u003e\n\u003cli\u003eEngineered from cast 16% silicon hypereutectic alloy ideal for air-cooled environments.\u003c\/li\u003e\n\u003cli\u003eLow thermal expansion rate allows for tighter piston-to-cylinder operating clearances.\u003c\/li\u003e\n\u003cli\u003eYields a 9.6:1 compression ratio with 80cc cylinder heads.\u003c\/li\u003e\n\u003cli\u003eIncludes all necessary components for installation: pistons, rings, wrist pins, and clips.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 style=\"margin:1.25em 0 0.5em\"\u003eCompatibility\u003c\/h3\u003e\n\u003cp style=\"margin:1em 0\"\u003eCompatible with 1984–1999 Harley-Davidson Big Twin motorcycles equipped with Evolution (Evo) engines requiring a +.040 in. oversize bore (89.9 mm \/ 3.538 in.).\u003c\/p\u003e\n\u003ch3 style=\"margin:1.25em 0 0.5em\"\u003eWhat's included\u003c\/h3\u003e\n\u003cul style=\"margin:1em 0\"\u003e\n\u003cli\u003e2 x Keith Black Hypereutectic Pistons\u003c\/li\u003e\n\u003cli\u003e1 x Complete Piston Ring Set\u003c\/li\u003e\n\u003cli\u003e2 x Wrist Pins\u003c\/li\u003e\n\u003cli\u003e1 x Set of Wrist Pin Clips\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 style=\"margin:1.25em 0 0.5em\"\u003eDownloads\u003c\/h3\u003e\n\u003cul style=\"margin:1em 0\"\u003e\u003cli style=\"margin:0 0 0.35em\"\u003e\u003ca href=\"https:\/\/images.rolliesspeedshop.com\/pdf\/KB305.040.pdf\" target=\"_blank\" rel=\"noopener nofollow\"\u003eDownload Product information ( PDF)\u003c\/a\u003e\u003c\/li\u003e\u003c\/ul\u003e\n\u003ctable class=\"pu-table\" style=\"width:100%;border-collapse:separate;border-spacing:0;border:0;box-shadow:none;outline:none;background:none;table-layout:fixed;margin:0\"\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd style=\"border:0;padding:0\"\u003e\n\u003ch3 style=\"margin:1.25em 0 0.5em\"\u003eFrequently asked questions\u003c\/h3\u003e\n\u003cstyle\u003e.pu-faq[open]\u003esummary .pu-faq-c{transform:rotate(180deg)}\u003c\/style\u003e\n\u003ctable class=\"pu-table\" style=\"width:100%;border-collapse:separate;border-spacing:0;border:0;box-shadow:none;outline:none;background:none;table-layout:fixed;margin:0 0 1em\"\u003e\u003ctbody\u003e\n\u003ctr\u003e\u003ctd style=\"border:0;padding:0;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003e\u003cdetails class=\"pu-faq\" style=\"padding:0.45em 0\"\u003e\u003csummary style=\"cursor:pointer;display:flex;align-items:center;justify-content:space-between;gap:10px;list-style:none\"\u003e\u003cstrong\u003eWhat compression ratio do these pistons provide?\u003c\/strong\u003e\u003csvg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 24 24\" width=\"18\" height=\"18\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"1.75\" stroke-linecap=\"round\" stroke-linejoin=\"round\" class=\"pu-faq-c\" style=\"width:1em;height:1em;flex:none;opacity:0.6;transition:transform 0.15s\" aria-hidden=\"true\"\u003e\u003cpath d=\"M6 9l6 6l6 -6\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\u003c\/summary\u003e\u003cp style=\"margin:0.4em 0 0\"\u003eThese pistons provide a 9.6:1 compression ratio when used with standard 80cc head chamber volumes.\u003c\/p\u003e\u003c\/details\u003e\u003c\/td\u003e\u003c\/tr\u003e\n\u003ctr\u003e\u003ctd style=\"border:0;padding:0;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003e\u003cdetails class=\"pu-faq\" style=\"padding:0.45em 0\"\u003e\u003csummary style=\"cursor:pointer;display:flex;align-items:center;justify-content:space-between;gap:10px;list-style:none\"\u003e\u003cstrong\u003eWhat is included in the piston kit?\u003c\/strong\u003e\u003csvg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 24 24\" width=\"18\" height=\"18\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"1.75\" stroke-linecap=\"round\" stroke-linejoin=\"round\" class=\"pu-faq-c\" style=\"width:1em;height:1em;flex:none;opacity:0.6;transition:transform 0.15s\" aria-hidden=\"true\"\u003e\u003cpath d=\"M6 9l6 6l6 -6\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\u003c\/summary\u003e\u003cp style=\"margin:0.4em 0 0\"\u003eThe kit includes two pistons, a matching ring set, wrist pins, and retaining clips.\u003c\/p\u003e\u003c\/details\u003e\u003c\/td\u003e\u003c\/tr\u003e\n\u003ctr\u003e\u003ctd style=\"border:0;padding:0;border-bottom:1px solid rgba(128,128,128,0.16);border-bottom:1px solid color-mix(in srgb,currentColor 12%,transparent)\"\u003e\u003cdetails class=\"pu-faq\" style=\"padding:0.45em 0\"\u003e\u003csummary style=\"cursor:pointer;display:flex;align-items:center;justify-content:space-between;gap:10px;list-style:none\"\u003e\u003cstrong\u003eWhat material are these pistons constructed from?\u003c\/strong\u003e\u003csvg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 24 24\" width=\"18\" height=\"18\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"1.75\" stroke-linecap=\"round\" stroke-linejoin=\"round\" class=\"pu-faq-c\" style=\"width:1em;height:1em;flex:none;opacity:0.6;transition:transform 0.15s\" aria-hidden=\"true\"\u003e\u003cpath d=\"M6 9l6 6l6 -6\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\u003c\/summary\u003e\u003cp style=\"margin:0.4em 0 0\"\u003eThey are cast from a hypereutectic aluminum alloy featuring a 16% silicon content designed for air-cooled applications.\u003c\/p\u003e\u003c\/details\u003e\u003c\/td\u003e\u003c\/tr\u003e\n\u003ctr\u003e\u003ctd style=\"border:0;padding:0\"\u003e\u003cdetails class=\"pu-faq\" style=\"padding:0.45em 0\"\u003e\u003csummary style=\"cursor:pointer;display:flex;align-items:center;justify-content:space-between;gap:10px;list-style:none\"\u003e\u003cstrong\u003eWhich motorcycle models and engines are compatible?\u003c\/strong\u003e\u003csvg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 24 24\" width=\"18\" height=\"18\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"1.75\" stroke-linecap=\"round\" stroke-linejoin=\"round\" class=\"pu-faq-c\" style=\"width:1em;height:1em;flex:none;opacity:0.6;transition:transform 0.15s\" aria-hidden=\"true\"\u003e\u003cpath d=\"M6 9l6 6l6 -6\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\u003c\/summary\u003e\u003cp style=\"margin:0.4em 0 0\"\u003eThey fit 1984–1999 Harley-Davidson Big Twin models equipped with the Evolution (Evo) engine.\u003c\/p\u003e\u003c\/details\u003e\u003c\/td\u003e\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e\n\u003c\/td\u003e\u003c\/tr\u003e\u003c\/tbody\u003e\u003c\/table\u003e","brand":"Keith Black Pistons","offers":[{"title":"Default Title","offer_id":49680944398592,"sku":"KB305.040","price":597.31,"currency_code":"NZD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0855\/0888\/2688\/files\/KB305.040.jpg?v=1788494607","url":"https:\/\/baychoppers.co.nz\/products\/keith-black-pistons-dome-top-pistons-kb305-040-for-big-twin-1984-1999","provider":"Bay Choppers NZ","version":"1.0","type":"link"}