KPMI Black Diamond Intake Valve - HD Evolution 1987-1999 — Harley-Davidson Electra Glide Classic, Softail Custom, Softail Heritage Classic (1984-1999)

KPMI Black Diamond intake valve for Harley Evolution engines, engineered with stainless steel and treated through a proprietary German impregnation process that reduces friction and improves wear resistance beyond conventional plating methods. One-piece forging design delivers superior flow characteristics and durability.

Features

• Black Diamond German impregnation process (.002″ depth)
• Superior wear and corrosion resistance vs. chrome/nickel plating
• Light, strong one-piece stainless steel forging
• Optimized flow profile design

Specifications

• Brand: KPMI
• Manufacturer Part #: 20-4171
• Length: 4.9 in
• Width: 3.6 in
• Height: 1.8 in
• Weight: 0.23 lbs

Fitment

Fits Harley-Davidson Evolution engines 1987–1999.

Frequently Asked Questions

What makes Black Diamond different from chrome-plated valves?

Black Diamond uses a German impregnation process that penetrates .002″ deep, reducing friction and outlasting chrome or nickel plating in wear and corrosion resistance.

Is this a single valve or a set?

This is one intake valve. Order the quantity needed for your engine build.

Will this fit my Twin Cam Harley?

No — this valve is engineered for Evolution-block engines only (1987–1999). Twin Cam engines require different valve specifications.

Do I need new valve guides and seats?

If your cylinder head is being rebuilt or freshened, have the valve seat and guide inspected by a qualified machine shop to ensure proper fitment and sealing.