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 2017+ Harley Milwaukee-Eight (M8) models, featuring a 4.320-inch bore and 4.625-inch stroke for substantial displacement increase. Installs into stock crankcases without machine work, retaining factory engine height while delivering significant power gains.

Features

• 4.320 in. bore with 4.625 in. stroke
• Works with stock crankcases — no machine work required
• Wrinkle black powder coat with highlight finish matches factory
• Multi-layered steel (MLS) head gaskets included
• Cubic inch cam cover badge included
• Retains stock engine height
• Made in USA

Specifications

• Brand: S&S Cycle
• Manufacturer Part #: 910-0848A
• Bore: 4.320 in.
• Stroke: 4.625 in.
• Weight: 29.56 lb
• Category: Engine Components / Piston Sets - Powersports
• Country of Origin: USA

Fitment

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

Frequently Asked Questions

What models does this fit?

Harley-Davidson 2017 and newer M8 models. Confirm your specific model year before ordering.

Do I need to have my crankcases machined?

No — this kit is designed to bolt into stock crankcases without any machine work or modifications.

Will this change my engine height?

No — the kit retains stock engine height, so your frame and bodywork stay in their original positions.

What gaskets are included?

Multi-layered steel (MLS) head gaskets are included to seal the new cylinder head to your case.

Is this a complete rebuild kit or just cylinders and pistons?

This is a cylinder and piston kit. You'll need to source valve train, cam, and internal engine components separately if doing a full rebuild.