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

S&S Cycle cylinder and piston kit for Harley Milwaukee-Eight (M8) engines, featuring a 4.250" bore and black granite finish with highlighted fins. Direct bolt-on installation increases displacement for more power without major engine teardown.

Features

• 4.250" bore cylinder
• Black granite finish with highlighted fins
• Bolt-on installation for M8 engines
• S&S Cycle recommends pairing with head bolts part number 900-1006 for big bore applications

Specifications

• Brand: S&S Cycle
• Manufacturer Part #: 910-0739
• Bore: 4.250 inches
• Finish: Black granite with highlighted fins
• Weight: 24.85 lb
• Category: Engine Components / Piston Sets - Powersports

Fitment

Fits Harley-Davidson Milwaukee-Eight (M8) models. S&S Cycle recommends using head bolts part number 900-1006 when installing big bore cylinder kits.

Frequently Asked Questions

What engine do these cylinders fit?

These are designed for Harley Milwaukee-Eight (M8) engines. Check your model year and engine code before ordering.

Do I need special head bolts?

S&S Cycle recommends pairing these big bore cylinders with their M8 head bolts (part number 900-1006) for proper clamping and reliability.

What is the bore size?

4.250 inches — larger than stock M8 cylinders to increase displacement and power output.

Will I need to tune my bike after installation?

Yes — big bore kits typically require fuel/air tuning with a ECU remapper to optimize performance and prevent running lean.