"Black Diamond" Valves for Harley-Davidson

Black Diamond valves are manufactured from a single piece of stainless steel and machined to a profile that provides optimal flow characteristics.
These very lightweight valves have been impregnated with a special process to reduce friction and improve resistance, including to corrosion.
Most valves are available in standard sizes, with standard or thinner stems, and with larger heads for high-performance engines.
Evolution Big Twin 1984-1999
Adm. Type
Stem Dia. .310"
Head diameter 1.840"
OEM 18074-83A