Kb Pistons Forged Alloy Piston - Pistons EVO 80ci 10.5:1 .020 — Harley-Davidson (1984-1999)

KB Pistons forged alloy piston set for EVO 80ci engines with 10.5:1 compression and .020 overbore. Made from 4032 forged alloy with 11% silicon content and fully machined for superior crack resistance under detonation or pre-ignition, making them ideal for street and race applications running power adders like NOS or boost.

Features

• 4032 forged alloy with 11% silicon content
• Superior crack resistance under detonation or pre-ignition
• Coated skirts on Twin Cam and Sportster applications
• All rings, wrist pins, and wrist pin locks included
• Sold as a pair

Specifications

• Brand: KB Pistons
• Manufacturer Part #: KB921C.020
• UPC: 800745155382
• Compression Ratio: 10.5:1
• Overbore: .020
• Engine Size: EVO 80ci
• Weight: 2.75 lbs
• Country of Origin: Mexico

Fitment

Designed for street and race applications with power adders such as NOS or boost on EVO 80ci engines.

Frequently Asked Questions

What's included in this piston set?

A pair of forged pistons, rings, wrist pins, and wrist pin locks — everything needed for installation.

Can I use these without a power adder?

Yes, these pistons work for street use. They're engineered to handle detonation and pre-ignition if you later add NOS or boost.

Are replacement rings available?

Yes, replacement rings are available as a special order from KB Pistons.

Do these pistons have coated skirts?

Yes, Twin Cam and Sportster applications feature coated skirts to reduce friction and wear.

What is the .020 overbore?

The .020 indicates the piston is sized .020 inches larger than stock bore diameter for a bored-and-stroked engine build.