S&S CYCLE Piston Kit - 1250 XL 920-0070

If you're running a Big Twin and want legitimate displacement gains without a complete engine rebuild, the S&S Cycle 1250cc piston kit delivers a straightforward path to increased cubic inches and power. Moving from 883cc or 1200cc to 1250cc gives you more swept volume, better low-end torque, and improved mid-range response—all from a bolt-on component that works with your existing cylinder heads. This is a proven formula for riders serious about performance without the complexity of a full engine overhaul.

The 1250cc pistons feature cast flat-top design optimized for 10.3:1 compression, striking a balance between performance and street-friendly operation. Installation is straightforward on compatible platforms, though cylinder boring is required for most applications. S&S recommends pairing these pistons with their CNC-ported cylinder heads for maximum results, though they're also compatible with stock 1200cc heads if you prefer a more conservative setup.

• Displacement: 883cc/1200cc to 1250cc
• Compression Ratio: 10.3:1
• Bore Size: 3-9/16"
• Piston Design: Cast flat-top
• Fitment: 1984-'99 HD Big Twins
• Compatible Cylinders: Stock 1200cc, 1986-'2003 883cc (requires boring)
• Not Compatible: 2004-'16 883cc cylinders
• Installation: Cylinder boring required
• Recommended Heads: S&S CNC-ported
• MPN: 920-0070