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

S&S Cycle 1250cc conversion kit for 1986-2021 Harley-Davidson Sportster models, upgrading 883cc or 1200cc engines to 1250cc displacement without requiring machine work or piston rebalancing. Kit includes forged pop-up pistons, S&S cylinders, gaskets, assembly lube, and instructions.

Features

• Forged 5cc pop-up 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 detailed instructions included

Specifications

• Brand: S&S Cycle
• Manufacturer Part #: 910-0692
• Displacement Increase: 883cc or 1200cc to 1250cc
• Piston Bore: 3-9/16"
• Weight: 22.75 lb
• Category: Engine Components / Piston Sets - Powersports

Fitment

Fits 1986-2021 Harley-Davidson Sportster models. 883 cylinder heads are not compatible with this kit and must be replaced.

Frequently Asked Questions

Does this kit require machine work or piston balancing?

No — the kit is engineered for direct installation without machining or rebalancing.

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

No — 883 cylinder heads are not compatible. You must use a 1200 head or later-model Sportster head.

What gaskets are included?

Head gaskets, base gaskets, exhaust gaskets, plus assembly lube and full installation instructions.

What else should I upgrade for best performance?

S&S recommends pairing the kit with CNC head porting, performance cams, exhaust, and intake upgrades to maximize power gains.

Will this kit fit my 1986-1990 Sportster?

Yes — this kit is designed to fit all Sportster models from 1986 through 2021.