S&S Cycle Cylinder & Piston Kits — Harley-Davidson Electra Glide, Electra Glide Classic, Electra Glide Ultra Classic (1955-2026)

S&S Cycle 107-124 cubic inch big bore cylinder and piston kit for Harley-Davidson Touring with Milwaukee-Eight engines. Bolt-on installation with no machining required, includes all gaskets and hardware. Forged pistons with 11:1 compression ratio deliver increased displacement and power without internal engine modifications.

Features

• Bolt-on installation — no machining required
• Forged pistons with 11:1 compression ratio
• 4.250" bore cylinder
• Includes all gaskets and installation hardware
• Wrinkle black finish with highlighted fins
• S&S recommends pairing with S&S head bolts (part 900-1006)

Specifications

• Brand: S&S Cycle
• Manufacturer Part #: 910-0625
• Bore Diameter: 4.250 inches
• Compression Ratio: 11:1
• Displacement Range: 107-124 cubic inches
• Weight: 31 lb
• Category: Engine Components / Piston Sets - Powersports

Fitment

Fits Harley-Davidson Touring models with Milwaukee-Eight (M8) engines. S&S Cycle recommends using S&S head bolts (part number 900-1006) for proper installation on all big bore applications.

Frequently Asked Questions

Do I need a machine shop for installation?

No. This is a bolt-on kit requiring no machining. All required gaskets and hardware are included.

Will this fit my Touring with M8 engine?

Yes — this kit is designed for Harley-Davidson Touring models with Milwaukee-Eight engines.

What compression ratio does this give me?

11:1 compression, which increases power output compared to stock engines.

Do I need to buy head bolts separately?

S&S Cycle recommends pairing this kit with their M8 head bolts (part number 900-1006) for proper installation and reliability.

What displacement will this add?

This big bore kit increases displacement from 107 to 124 cubic inches, depending on your stock engine size.