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

S&S Cycle big-bore cylinder and piston kit for 2017+ Harley-Davidson Touring models, upgrades 107 cubic-inch engines to 124 cubic inches with forged pistons and an 11:1 compression ratio. Bolt-on installation with no machining required; includes all gaskets and hardware needed.

Features

• Forged pistons with 11:1 compression ratio
• 4.250 in bore × 4.375 in stroke
• Bolt-on installation — no machining
• Includes gaskets and mounting hardware
• Not recommended for Tri-Glide or three-wheel models

Specifications

• Brand: S&S Cycle
• Manufacturer Part #: 910-0625A
• Bore × Stroke: 4.250 in × 4.375 in
• Displacement Upgrade: 107 to 124 cubic inches
• Compression Ratio: 11:1
• Weight: 30.6 lb
• Category: Engine Components / Piston Sets - Powersports

Fitment

Fits 2017 and newer Harley-Davidson Touring models with 107 cubic-inch engines. Not compatible with Tri-Glide or three-wheel models.

Frequently Asked Questions

What's included in the kit?

Cylinder, pistons, rings, gaskets, and all bolts and hardware needed for bolt-on installation.

Do I need to have my head machined or ported?

No — this is a true bolt-on kit. No machine work required.

Will this fit my Tri-Glide?

No — S&S does not recommend this kit for Tri-Glide or other three-wheel models.

What fuel octane do I need with 11:1 compression?

11:1 compression typically requires 91-octane fuel minimum; premium 93-octane is recommended to prevent detonation and maximize performance.

Can I install this myself, or do I need a shop?

Piston and cylinder installation requires engine disassembly and proper torque specs. Most riders use a shop with M-Series Harley experience.