S&S Cycle Cylinder & Piston Kits — Harley-Davidson Street Glide, Softail Fat Boy 114, Road King Special (2017-2026)

S&S Cycle 4.250 in bore big bore cylinder set for 2017+ Harley-Davidson M8 engines, finished in black granite with highlighted fins. Unhoned cylinders ship ready for final honing and piston fitment as part of a complete rebuild kit.

Features

• 4.250 in bore big bore cylinders
• Black granite finish with highlighted fins
• Unhoned — ready for final honing
• Includes mounting hardware

Specifications

• Brand: S&S Cycle
• Manufacturer Part #: 910-0739A
• Bore Size: 4.250 in
• Finish: Black granite with highlights
• Condition: Unhoned
• Weight: 24.85 lb
• Category: Engine Components / Piston Sets - Powersports

Fitment

Fits 2017 and newer Harley-Davidson Milwaukee-Eight (M8) models.

Frequently Asked Questions

Do these cylinders come honed?

No — these ship unhoned. Final honing must be done to match your piston kit and engine build specifications.

Will this fit my 2016 or earlier Harley?

No — this kit is engineered for 2017+ M8 engines only. Twin Cam engines require a different cylinder kit.

What piston size pairs with a 4.250 in bore?

Check S&S Cycle's piston catalog for M8-compatible pistons matched to 4.250 in bore cylinders — proper sizing is critical for engine function.

Do I need special tools to install these?

Big bore cylinder installation requires engine removal, proper torque specs, and precision honing. Professional machine shop installation is recommended.