KPMI Black Diamond Exhaust Valve - O/S Ex. Valve EVO/Twin CAM `1984-2004 — Harley-Davidson (1984-2017)

KPMI Black Diamond exhaust valve for Harley EVO and Twin Cam engines 1984-2004, forged stainless steel with a proprietary German impregnation process that hardens the surface to .002" depth. Black Diamond coating reduces friction and resists corrosion and wear better than chrome or nickel plating.

Features

• One-piece stainless steel forging
• Black Diamond surface impregnation (.002" depth)
• Reduced friction and superior wear resistance
• Optimized flow profile
• Lightweight construction

Specifications

• Brand: KPMI
• Manufacturer Part #: 20-20920
• Length: 4.4 in
• Width: 2 in
• Height: 0.5 in
• Weight: 0.5 lbs

Fitment

Fits Harley-Davidson EVO and Twin Cam engines, 1984-2004 model years.

Frequently Asked Questions

What is the Black Diamond process?

A German impregnation process that hardens the valve surface to .002" depth, improving wear resistance and corrosion protection beyond standard chrome or nickel plating.

Will this fit my 2005+ Twin Cam engine?

No — this part is for EVO and Twin Cam engines through 2004. 2005-newer M8 and updated Twin Cam engines require different valve specifications.

Is this a complete valve assembly?

This is the valve head only. You'll need to confirm your engine's full valve specification and seat compatibility before ordering.

How much lighter is this than OEM valves?

KPMI Black Diamond valves are engineered as lightweight one-piece forgings, reducing rotating mass compared to many stock valves — exact weight savings depend on the original equipment.