Kb Pistons Forged Alloy Piston - Pistons EVO 80ci 10.5:1 .010 — Harley-Davidson (1984-1999)

KB Pistons forged 4032 alloy pistons for EVO 80ci engines at 10.5:1 compression with .010 oversized bore. Made from 4032 forged alloy with 11% silicon content for superior crack resistance under detonation and pre-ignition in high-output street or race applications.

Features

• 4032 forged alloy with 11% silicon content
• Forged and fully machined construction
• Superior crack resistance under detonation
• Coated skirts on Twin Cam and Sportster applications
• Rings, wrist pins, and wrist pin locks included
• Sold as a pair

Specifications

• Brand: KB Pistons
• Manufacturer Part #: KB921C.010
• UPC: 800745155375
• Compression Ratio: 10.5:1
• Bore Size: .010 oversized
• Engine: EVO 80ci
• Length: 9.4 in
• Width: 4.8 in
• Height: 4.6 in
• Weight: 2.75 lbs
• Country of Origin: Mexico

Fitment

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

Frequently Asked Questions

What's included with these pistons?

The pair of pistons, piston rings, wrist pins, and wrist pin locks are all included. No additional ordering needed.

Can I use replacement rings later?

Replacement rings for these pistons are available as special order through KB Pistons.

Why is the compression ratio 10.5:1?

This higher compression ratio is designed to handle boost and NOS power adders while maintaining stable detonation resistance.

Do I need to order wrist pin locks separately?

No — wrist pin locks are included. Note that you need 2 locks per piston (4 total for a pair).

Are these pistons street-legal?

These pistons are suitable for both street and race applications. Local regulations may apply — verify with your tuner or engine builder.