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

S&S Cycle piston and cylinder kit for 2017+ Harley-Davidson Milwaukee-Eight (M8) engines, sized at 4.250-inch bore and 4.625-inch stroke in standard configuration. Direct replacement for stock pistons and cylinders to restore or upgrade engine performance.

Features

• 4.250 in bore x 4.625 in stroke
• Standard sizing
• For 2017+ M8 engines
• S&S Cycle engineering

Specifications

• Brand: S&S Cycle
• Manufacturer Part #: 920-0149
• Bore x Stroke: 4.250 in x 4.625 in
• Sizing: Standard
• Category: Engine Components / Piston Sets - Powersports
• Weight: 3.22 lb

Fitment

Fits 2017 and newer Harley-Davidson Milwaukee-Eight (M8) engines in standard bore and stroke sizing.

Frequently Asked Questions

Will this fit my 2017+ Harley M8 engine?

Yes — this kit is designed for all 2017 and newer Harley-Davidson Milwaukee-Eight engines in standard sizing.

Is this a direct replacement for stock pistons and cylinders?

Yes. This kit replaces the factory pistons and cylinders without requiring block modifications for standard M8 applications.

What's included in the kit?

Pistons and cylinders sized to 4.250-inch bore and 4.625-inch stroke. Check the manual for gaskets, rings, and hardware requirements.

Will this increase engine displacement?

No — standard sizing maintains the original M8 displacement. S&S offers overbore kits if you want larger displacement.