KPMI Powdered Metal 44.6mm Valve Seat - Harley Evolution Big Twin & Sportster
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.
Replace worn valve seats in your Harley Evolution Big Twin or Sportster with a KPMI powdered metal valve seat. This 44.6mm seat is engineered for durability and performance, resisting microwelding and recession under demanding conditions. It's designed to handle a wide range of fuel types, making it a reliable choice for your V-twin engine.
Why riders pick this
- Proprietary powdered metal resists microwelding
- Compatible with leaded, unleaded, methanol, and ethanol fuels
- Excellent thermal stability for street and performance riding
- Generous leading-edge radius for easier installation
- Designed for Harley Evolution Big Twin and Sportster engines
When you're pushing your Harley Evolution Big Twin or Sportster, every engine component needs to stand up to the heat and stress. KPMI valve seats are crafted from a proprietary powdered metal material that excels in high-performance applications. This 44.6mm valve seat provides excellent thermal stability, crucial for consistent engine operation whether you're on the street or the track.
Engineered for Extreme Conditions
- Proprietary powdered metal material resists microwelding and recession
- Compatible with leaded, unleaded, methanol, and ethanol fuel blends
- Generous leading-edge radius simplifies installation into the cylinder head
- Maintains structural integrity under high thermal loads for reliability
Upgrade with Confidence
Installing new valve seats is a critical step in any top-end rebuild or performance upgrade. These KPMI valve seats are a direct replacement for your Harley Evolution Big Twin or Sportster, ensuring a precise fit and reliable performance. Pair them with fresh valves and guides for a complete cylinder head refresh that will restore lost power and improve engine longevity.
Specifications
- Brand: KPMI
- Manufacturer Part #: 10-SC446
- Length: 2.05 in
- Width: 3.55 in
- Height: 0.95 in
- Weight: 0.11 lbs
Common questions
Will this valve seat work with ethanol fuel blends?
Yes, Kibblewhite's proprietary material is fully compatible with ethanol and methanol fuel blends, as well as leaded and unleaded gasoline.
What makes this seat resistant to recession?
The powdered metal material resists microwelding, which is a primary cause of valve seat and valve face wear over time.
Is this a direct replacement for my factory valve seat?
This KPMI valve seat is designed to replace the original components in 1984-1999 Harley Evolution Big Twin and Sportster engines. Always confirm fitment with your specific model year.
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 | 191-57092 |
| WEIGHT | 0.11 lb |
