{"product_id":"kpmi-black-diamond-exhaust-valve-hd-evolution-1987-1999-191-17002","title":"KPMI Black Diamond Exhaust Valve - HD Evolution 1987-1999 — Harley-Davidson (1984-1999)","description":"\u003cp\u003eKPMI Black Diamond exhaust valve for Harley Evolution engines, precision-forged from stainless steel and treated with a proprietary German impregnation process that hardens the surface to .002\" depth. Delivers superior wear resistance and corrosion protection compared to chrome or nickel plating, with reduced friction for longer valve life.\u003c\/p\u003e\n\u003ch2\u003eFeatures\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eStainless steel one-piece forging\u003c\/li\u003e\n  \u003cli\u003eGerman Black Diamond® impregnation process\u003c\/li\u003e\n  \u003cli\u003eImproved wear resistance and corrosion protection\u003c\/li\u003e\n  \u003cli\u003eExcellent flow characteristics\u003c\/li\u003e\n  \u003cli\u003eLightweight construction\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e KPMI\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer Part #:\u003c\/strong\u003e 20-4170\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLength:\u003c\/strong\u003e 3.55 in\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWidth:\u003c\/strong\u003e 4.7 in\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHeight:\u003c\/strong\u003e 1.55 in\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.19 lbs\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eFitment\u003c\/h2\u003e\n\u003cp\u003eFits Harley-Davidson Evolution engines, 1987-1999 model years.\u003c\/p\u003e\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003ch3\u003eIs this an intake or exhaust valve?\u003c\/h3\u003e\n\u003cp\u003eThis is an exhaust valve. KPMI makes separate part numbers for intake valves.\u003c\/p\u003e\n\u003ch3\u003eWhat makes Black Diamond® different from standard stainless valves?\u003c\/h3\u003e\n\u003cp\u003eThe German impregnation process hardens the surface to .002\" depth, reducing friction and improving wear resistance beyond standard chrome or nickel plating.\u003c\/p\u003e\n\u003ch3\u003eWill this fit my 2000+ Twin Cam engine?\u003c\/h3\u003e\n\u003cp\u003eNo — this valve is for Evolution engines only (1987-1999). Twin Cam models require different valve part numbers.\u003c\/p\u003e\n\u003ch3\u003eDo I need new valve seats when I install these?\u003c\/h3\u003e\n\u003cp\u003eCheck your cylinder head condition. If seats are pitted or worn, have them resurfaced or replaced by a machine shop during your engine rebuild.\u003c\/p\u003e","brand":"KPMI","offers":[{"title":"Default Title","offer_id":53035004854383,"sku":"191-17002","price":29.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0608\/6734\/6543\/files\/output_3cd91577-0de1-424a-8d15-236e24a8c8b5.png?v=1779559000","url":"https:\/\/vtwinbikers.com\/products\/kpmi-black-diamond-exhaust-valve-hd-evolution-1987-1999-191-17002","provider":"Vtwinbikers","version":"1.0","type":"link"}