Kb Pistons Hypereutectic Cast Piston - Pistons Twin CAM 88ci 8.8:1 .020 — Harley-Davidson Road King, Road King Classic, Electra Glide (1999-2007)

KB Pistons Hypereutectic cast piston for Twin CAM 88ci engines with 8.8:1 compression ratio and .020 oversized bore. Cast from a 16% silicon alloy that resists thermal expansion, allowing tight piston-to-cylinder clearances ideal for air-cooled motors running stock to mild tune on pump fuel.

Features

• Hypereutectic alloy with 16% silicon content
• Low thermal expansion rate
• Tight piston-to-cylinder clearances
• Reduced wear and quieter engine operation
• Suited for stock to mild compression ratios up to 10.5:1

Specifications

• Brand: KB Pistons
• Manufacturer Part #: KB425C.020
• UPC: 800745067739
• Bore Size: .020 oversized
• Compression Ratio: 8.8:1
• Engine Displacement: Twin CAM 88ci
• Length: 9.5 in
• Width: 4.8 in
• Height: 4.6 in
• Weight: 2.5 lbs
• Country of Origin: Mexico

Fitment

Fits Harley-Davidson Twin CAM 88ci air-cooled engines. Best suited for stock or mild compression ratios up to 10.5:1 running on pump fuel.

Frequently Asked Questions

What compression ratio is this piston rated for?

8.8:1 compression ratio. These hypereutectic pistons are best suited for stock or mild tunes up to 10.5:1 on pump fuel.

Why hypereutectic over forged pistons?

Hypereutectic alloy has 16% silicon content, offering high thermal barrier properties and low expansion rates. Ideal for air-cooled engines with tight clearances and reduced wear.

Is this a .020 oversized piston?

Yes — this is a .020 oversized bore piston (KB425C.020). Confirm your cylinder bore size before ordering.

Does this piston require any special installation procedures?

Follow the manufacturer's guidelines for piston ring gap, clearance, and installation torque specifications.