KPMI Black Diamond Oversized Exhaust Valve - Harley Evolution & Twin Cam
About KPMI
Kibblewhite Precision Machining supplies valves, valve springs, guides and complete top-end kits used by professional V-twin engine builders. Its black diamond valves and spring kits are a standard specification on high-lift cam builds.
Unleash the full potential of your Harley Evolution or Twin Cam engine with the KPMI Black Diamond Oversized Exhaust Valve. Engineered from a robust one-piece stainless steel forging, this valve is built to withstand the demands of high-performance V-twin operation. Its advanced surface treatment ensures superior wear resistance and reduced friction.
Why riders pick this
- Forged stainless steel construction for ultimate strength
- Black Diamond surface for superior wear and friction reduction
- Enhanced corrosion resistance over standard plating
- Optimized flow profile for improved exhaust efficiency
When you're chasing every last bit of power from your Evolution or Twin Cam, every component matters. The KPMI Black Diamond exhaust valve isn't just a replacement; it's an upgrade. The proprietary German impregnation process hardens the valve surface to a significant depth, providing a level of durability that far surpasses standard chrome or nickel plating. This means your engine can run harder and longer, delivering consistent performance ride after ride.
Engineered for Extreme Durability
- One-piece stainless steel forging for maximum strength
- Black Diamond surface impregnation reduces friction and resists wear
- Enhanced corrosion protection for extended valve life
- Optimized flow profile supports improved exhaust scavenging
Optimizing Your V-Twin Performance
This oversized exhaust valve is a critical component for riders looking to maximize their engine's efficiency and longevity. Whether you're refreshing a high-mileage Evo or building a performance-oriented Twin Cam, the KPMI Black Diamond valve provides the foundation for reliable power. Pair it with complementary valvetrain components for a comprehensive upgrade that truly transforms your ride.
Specifications
- Brand: KPMI
- Manufacturer Part #: 20-20920
- Length: 4.4 in
- Width: 2 in
- Height: 0.5 in
- Weight: 0.5 lbs
Common questions
What is the Black Diamond process?
It's a proprietary German impregnation process that hardens the valve surface to .002" depth, significantly improving wear resistance and corrosion protection beyond standard chrome or nickel plating.
Will this valve fit my 2005+ Twin Cam engine?
No, this specific valve is designed for Evolution and Twin Cam engines through the 2004 model year. Later Twin Cam and Milwaukee-Eight engines require different valve specifications.
Is this a direct replacement for my stock exhaust valve?
This valve is an oversized option designed for performance applications. While it's a direct fit for compatible Evolution and Twin Cam engines, it's best to confirm fitment with your cylinder head setup and engine builder.
Ordering from Vtwinbikers
- Brand new, sourced through authorized US distribution — never used, never grey-market.
- Not sure it fits? Use Shop by Bike to filter by your year and model, or email us and we will confirm before you order.
- Harley-Davidson and Indian Motorcycle is all we do, so you are talking to people who ride what you ride.
| BRAND | KPMI |
| TYPE | Engine |
| SKU | 191-17035 |
| WEIGHT | 0.5 lb |
