Kibblewhite intake valves are a great upgrade from your O.E.M. motorcycle valves due to their superior performance and outstanding reliability. All KPMI Black Diamond stainless steel valves are impregnated by a special German process to a depth of 0.002", with a surface build up of 0.0002". This "Black Diamond" process improves wear properties, reduces friction, and provides resistance to corrosion and wear that is superior to chrome and nickel electrolysis plating. Each valve is designed using Finite Element Analysis software, and profiles are tested on Kibblewhites computerized flow bench. Black Diamond Valves are light, strong, one-piece forgings with profiles that provide excellent flow characteristics and will outlast titanium valves.Detailed Specifications: Type: Valve, intake, Black Diamond. Material: Stainless steel. Quantity: 1. Head diameter: 1.418" / 36.00 mm. Stem diameter: 0.2155". Tulip: 20. Overall length: 3.210". Remarks: Standard head diameter. Notes: Kibblewhite valves are sold individually. You must use KPMI Spring Kit 60-60700 when installing Black Diamond valves.