{"product_id":"drag-specialties-spark-plugs-for-1975-1999-big-twin-e18-6657sds","title":"Drag Specialties Spark Plugs for 1975–1999 Big Twin, E18-6657SDS","description":"Spark Plugs - '75-'99 Big Twin\n\u003cp\u003eUpgrade the ignition performance of your compatible 1975–1999 Big Twin motorcycle with Drag Specialties Spark Plugs, part number E18-6657SDS. Designed for dependable service in demanding motorcycle applications, these spark plugs combine durable construction with consistent electrical performance. The black ceramic body and bold red Drag Specialties logo provide a distinctive appearance while supporting reliable operation.\u003c\/p\u003e\u003cp\u003eThe high-quality insulator is made from 95% pure alumina for strong resistance to heat shock and superior electrical insulation. Its multi-rib design helps eliminate flashover, promoting dependable spark delivery. A nickel-plated housing resists oxidation and corrosion, while the copper core electrode provides excellent electrical and heat conductivity. Together, these features help support long spark plug service life and stable ignition performance.\u003c\/p\u003e\u003cp\u003eDrag Specialties uses multi-layer gaskets and a heat-crimping process to create a leak-free, gas-tight seal. These spark plugs are intended for fitment on 1975–1999 Big Twin applications; verify the motorcycle model, engine configuration, and original-equipment specifications before installation. Supplied under manufacturer and vendor part number E18-6657SDS, this set is a practical replacement choice for routine maintenance or ignition system service.\u003c\/p\u003e\u003cp\u003e\u003cb\u003eFeatures:\u003c\/b\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eFitment: Designed for compatible 1975–1999 Big Twin motorcycle applications\u003c\/li\u003e\n\u003cli\u003eBrand: Drag Specialties\u003c\/li\u003e\n\u003cli\u003eManufacturer part number: E18-6657SDS\u003c\/li\u003e\n\u003cli\u003eVendor part number: E18-6657SDS\u003c\/li\u003e\n\u003cli\u003eInsulator: 95% pure alumina construction resists heat shock and provides superior insulation\u003c\/li\u003e\n\u003cli\u003eInsulator design: Multi-rib profile helps eliminate flashover\u003c\/li\u003e\n\u003cli\u003eHousing: Nickel-plated finish helps prevent oxidation and corrosion\u003c\/li\u003e\n\u003cli\u003eSealing: Multi-layer gaskets and heat crimping provide a leak-free, gas-tight seal\u003c\/li\u003e\n\u003cli\u003eElectrode: Copper core supports electrical and heat conductivity\u003c\/li\u003e\n\u003cli\u003eAppearance: Black ceramic body with a bold red Drag Specialties logo and script\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"DRAG SPECIALTIES","offers":[{"title":"Default Title","offer_id":67569457430763,"sku":"21030198","price":15.85,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0611\/3882\/9547\/files\/9143.png?v=1790805890","url":"https:\/\/ctracingservices.com\/products\/drag-specialties-spark-plugs-for-1975-1999-big-twin-e18-6657sds","provider":"Cascade Tire \u0026 Racing Services","version":"1.0","type":"link"}