S&S Cycle Conversion Kits — 1986-2021 Harley-Davidson Sportster Models

S&S Cycle 1250cc conversion kit for 1986-2021 Harley Sportster models, converting stock 883cc or 1200cc displacement without requiring machine work or piston rebalancing. Kit includes forged pistons, cylinders, gaskets, and assembly lube with detailed installation instructions.

Features

• Forged flat-top pistons with coated skirts
• S&S 3-9/16" bore cylinders
• Complete gasket set included (head, base, exhaust)
• No machining or rebalancing required
• Assembly lube and instructions included

Specifications

• Brand: S&S Cycle
• Manufacturer Part #: 910-0689
• Displacement Increase: 883cc or 1200cc to 1250cc
• Piston Bore: 3-9/16 inch
• Weight: 22.1 lb
• Category: Engine Components / Piston Sets - Powersports

Fitment

Fits all Harley-Davidson Sportster models 1986 through 2021. Note: 883cc cylinder heads are not compatible with this kit and cannot be reused.

Frequently Asked Questions

Can I use my stock 883 cylinder head with this kit?

No — 883 cylinder heads are not compatible with this conversion kit. You will need a 1200cc head or upgrade to a performance head.

Do I need to have the pistons balanced or cylinders machined?

No — the kit is designed to install without balancing work or machine shop services required.

What gaskets are included?

The kit includes head gaskets, base gaskets, exhaust gaskets, assembly lube, and full installation instructions.

Will this kit alone give me the best power gains?

The base kit delivers the displacement bump. S&S recommends pairing it with CNC head porting, performance cams, and upgraded exhaust and intake for maximum performance.

Does this fit both 883 and 1200 Sportsters?

Yes — the kit converts both 883cc and 1200cc models up to 1250cc displacement.