Kb Pistons Hypereutectic Cast Piston 8.6:1 .020 Over - Harley Evolution 80ci
About Kb Pistons
KB Performance Pistons builds hypereutectic and forged pistons for American V-twin engines, and is a long-standing choice for big-bore and stock-replacement rebuilds where budget and durability both matter.
Refresh your Harley Evolution 80ci engine with a Kb Pistons Hypereutectic Cast Piston, sized .020 over stock bore. This piston features an 8.6:1 compression ratio and is cast from a 16% high-silicon alloy, engineered to reduce thermal expansion and improve ring seal in air-cooled Harley engines running pump fuel.
Why riders pick this
- Hypereutectic 16% silicon alloy for thermal stability
- Low thermal expansion allows tight clearances
- Designed for stock to mild 8.6:1 compression ratios
- .020 inch oversize for cylinder rebuilds
- Reduces engine noise and wear in air-cooled engines
When it's time for an engine rebuild, choosing the right piston is paramount for restoring performance and ensuring longevity. Kb Pistons Hypereutectic Cast Pistons offer a precise fit and reliable operation for your Evolution 80ci. The advanced alloy design helps to minimize engine noise and wear, providing a solid foundation for your V-twin's power plant.
Advanced Design for EVO Engines
- 16% silicon hypereutectic alloy reduces thermal expansion
- Allows for tighter piston-to-cylinder clearances for better seal
- Designed for stock to mild compression ratios up to 10.5:1
- .020 inch oversize for rebuilding cylinders
- Optimized for air-cooled Harley-Davidson Evolution 80ci engines
Restore Power and Reliability
These pistons are an excellent choice for riders undertaking a full engine rebuild on their Evolution 80ci. The .020 inch oversize requires cylinder boring, ensuring a fresh sealing surface and optimal performance. They are engineered to deliver consistent power and a long service life, whether your bike is a Touring, Softail, or Dyna model, keeping you on the road with confidence.
Specifications
- Brand: KB Pistons
- Manufacturer Part #: KB258.020
- UPC: 800745060389
- Compression Ratio: 8.6:1
- Bore Size: .020 over
- Engine Displacement: 80 cubic inches (EVO)
- Weight: 2.65 lbs
- Country of Origin: Mexico
Common questions
What does ".020 over" mean for these pistons?
.020 over means the piston is sized .020 inches larger than the standard bore. This requires your cylinders to be bored out to match the new piston size during an engine rebuild, creating a fresh surface for optimal ring seal.
Are these pistons suitable for high-performance builds with forced induction?
These hypereutectic pistons are rated for stock to mild compression ratios up to 10.5:1 on pump fuel. For higher compression, forced induction, or race fuel applications, forged pistons specifically designed for those conditions are generally recommended.
Will these pistons fit my specific Harley Evolution 80ci model?
These pistons are designed for Harley Evolution 80 cubic inch air-cooled engines found in various Touring, Softail, and Dyna models. It is crucial to confirm fitment for your exact year and model before ordering and ensure your cylinders are machined to the correct oversize.
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 | Kb Pistons |
| TYPE | Piston kits & Components |
| SKU | 824-01003 |
| WEIGHT | 2.65 lb |
| 8.6 | 1 Compression |
