S&S CYCLE - 91-9001 - 3-5/8” Big Bore Cylinder and Piston Kit
When it is time for a top-end rebuild, the piston you choose sets the ceiling on everything that comes after, and the S&S CYCLE 91-9001 delivers the precision that serious riders and race mechanics expect. Cylinder and piston kit can be used to build an 88” engine, or to replace the cylinders and piston in an engine with an existing S&S stock bore stroker kit, ensuring dimensional accuracy from the first start-up. Includes 3-5/8” bore high tensile cast iron cylinders, forged pistons with rings and wristpins, head gaskets, stainless steel head bolts with washers, base nuts and base gaskets, which means it holds tight tolerances longer and runs cooler. Can be used in engines with 4-1/4” flywheels, and made in the U.S.A. helps the new piston seat properly during break-in. Crankcases must be bored to accept the larger 3-5/8” cylinders and stock flywheel assembly should be rebalanced.. Whether refreshing a worn top-end or building a motor from scratch, the 91-9001 gives you a solid foundation for a long-lasting engine. Sold as a complete kit.
Features
- Cylinder and piston kit can be used to build an 88” engine, or to replace the cylinders and piston in an engine with an existing S&S stock bore stroker kit
- Includes 3-5/8” bore high tensile cast iron cylinders, forged pistons with rings and wristpins, head gaskets, stainless steel head bolts with washers, base nuts and base gaskets
- 88”, 7.5:1 compression
- Can be used in engines with 4-1/4” flywheels
- Made in the U.S.A.
- Crankcases must be bored to accept the larger 3-5/8” cylinders and stock flywheel assembly should be rebalanced.
Specs
- Compression Ratio: 7.5:1
- Units: Kit
- Displacement: 88”
- Material: Iron
- Riding Style: Street
- Stroke Length: 4.250”
- Color/Finish: Gloss Black
- Style: Big Bore
- Bore Size: 3.625”
- Material: Cast
- Product Name: Cylinder and Piston Kit
Frequently Asked Questions - S&S CYCLE - 91-9001 - 3-5/8” Big Bore Cylinder and Piston Kit
How do I know if this part fits my vehicle?
Check the fitment information listed on this page against your exact year, make, model, and (where applicable) trim, engine size, or configuration. If your exact vehicle isn't listed, or you're not sure, use the product chat on this page or contact our support team before ordering - we're glad to help confirm fitment.
What does it mean if a product is listed as universal fit?
Universal fit means the product is designed to work across a range of vehicles, not that it's guaranteed to fit every one. Compare the listed measurements, mounting requirements, and connector or hardware specs against your specific vehicle before ordering, since some installations may need additional hardware or minor fabrication.
Where can I find installation instructions for this product?
General installation notes are provided above where available. For detailed step-by-step instructions, refer to the manufacturer's documentation included with the product, or use the product chat on this page for questions about difficulty, required tools, or whether professional installation is recommended.
What if I have more questions about this product?
Use the product chat on this page for fitment, specs, installation, and compatibility questions, or contact our support team directly for help before you order.
