Kb Pistons Hypereutectic Cast Piston - Pistons EVO 80ci 9.6:1 .020 — Harley-Davidson (1984-1999)

KB Pistons Hypereutectic cast piston for Harley EVO 80ci engines, engineered with 16% silicon content for superior thermal properties and minimal expansion. Delivers tight piston-to-wall clearances, optimal ring seal, and quieter operation in stock and mild compression builds up to 10.5:1 on pump fuel.

Features

• Hypereutectic alloy with 16% silicon content
• Low thermal expansion rate
• Tight piston-to-cylinder clearances
• Ideal for air-cooled EVO engines
• Stock to mild compression ratios up to 10.5:1

Specifications

• Brand: KB Pistons
• Manufacturer Part #: KB305.020
• UPC: 800745130082
• Displacement: EVO 80ci
• Compression Ratio: 9.6:1
• Oversized: .020 in
• Weight: 2.8 lbs
• Country of Origin: Mexico

Fitment

Fits Harley-Davidson air-cooled EVO 80-cubic-inch engines. Optimized for stock through mild-compression applications running on pump fuel.

Frequently Asked Questions

Will this piston work with my high-compression EVO build?

No — KB Hypereutectic pistons are rated for compression ratios up to 10.5:1. High-compression builds over 10.5:1 require sintered or forged pistons.

What compression ratio does this piston deliver?

9.6:1 compression with stock cylinder heads. Final ratio depends on your complete cylinder and head combination.

Is this a .020 oversized piston?

Yes — this is a .020-inch oversized piston, requiring cylinders bored .020 over stock.

Why choose hypereutectic over forged?

Hypereutectic pistons offer lower cost, adequate durability for stock-to-mild engines, and excellent ring seal with minimal noise. Forged pistons are stronger but more expensive and better suited for high-compression or high-RPM builds.