Kb Pistons Hypereutectic Cast Piston - Pistons EVO 80ci 8.6:1 .020 — Harley-Davidson (1984-1999)

KB Pistons Hypereutectic Cast Piston for EVO 80ci engines at 8.6:1 compression, sized .020 over stock bore. Cast from a 16% high-silicon alloy that reduces thermal expansion and improves ring seal in air-cooled Harley engines running pump fuel.

Features

• 16% silicon hypereutectic alloy
• Low thermal expansion rate
• Tight piston-to-cylinder clearances
• Designed for stock to mild compression ratios up to 10.5:1
• Reduces engine noise and wear

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

Fitment

Fits air-cooled EVO 80ci engines. Hypereutectic design is optimized for stock or mild compression ratios up to 10.5:1 on pump fuel.

Frequently Asked Questions

Will these pistons work with higher compression ratios?

Hypereutectic pistons are rated for compression ratios up to 10.5:1. Higher ratios require forged pistons designed for boost or race fuel.

What does .020 over mean?

.020 over means the piston is sized .020 inches larger than stock bore, requiring a .020 bore hone to fit properly.

Why choose hypereutectic over forged?

Hypereutectic pistons have lower thermal expansion, allowing tighter ring seal and quieter running in stock or mildly modified air-cooled engines on pump fuel.

Do these require any special installation prep?

Ensure your cylinders are bored and honed to the correct .020 over size. Have a machine shop measure and prepare the bore before installation.