S&S Cycle Crankcase Set 31-0000 for Harley Big Twin 1984–1991 (FXST/FLT/FXR/FLST)

Ready-to-assemble crankcase set for 1984–1991 Harley-Davidson Big Twin V2 engines, designed to accept flywheels up to 8-1/2 inches in diameter within a stock bore case. Manufactured in the USA with durable materials for dependable rebuilds.

• Timken left-side bearing race assembly
• seal
• seal spacer
• oil pump drive bushing
• needle bearing
• pinion race (pressed in and line honed)

Includes cylinder studs, nickel-plated case bolts, crankcase fittings, and timing/magnetic drain plug for a complete installation. The Manufacturer’s Statement of Origin provides authenticity. For best results, pair with S&S #12-8002 oil pump assembly to ensure proper oil flow and longevity.

Fitment covers Harley-Davidson FLST, FLT, FXR, and FXST models from 1984 through 1991.

Ideal for professional rebuilds, restorations, or custom engine builds requiring a ready-to-assemble crankcase set that aligns with OEM specifications.

Natural crankcase set for 1984-1991 Big Twin V2 type engine comes ready to assemble.

The S&S Cycle Part 31-0000 crankcase set is a comprehensive engine component package designed for Harley Davidson FXST and FLT models from 1984 to 1991. Crafted in the USA, this set features a stock bore case that can accommodate flywheels up to 8-1/2 inches in diameter, making it suitable for a range of cruiser applications. The set includes a Timken left side bearing race assembly, a seal, a seal spacer, an oil pump drive bushing, a needle bearing, and a pinion race that is pressed in and line honed for precise assembly. These components ensure a reliable foundation for your engine rebuild or upgrade, maintaining optimal performance and durability. Additionally, the set comes with cylinder studs, nickel-plated case bolts, crankcase fittings, and a timing and magnetic drain plug, offering all necessary hardware for a complete installation. The inclusion of the Manufacturer’s Statement of Origin provides assurance of authenticity and quality. It is recommended to use this crankcase set with the S&S #12-8002 oil pump assembly for best results, ensuring proper oil flow and engine longevity. This product is ideal for professional rebuilds, restorations, or custom engine builds, providing a high-quality, ready-to-assemble crankcase that meets or exceeds OEM standards. Trust S&S Cycle for durable, precision-engineered parts that keep your Harley running smoothly for miles to come.

Features:

• Includes Timken left-side bearing race assembly, seal, seal spacer, oil pump drive bushing, needle bearing, and pinion race for a complete crankcase rebuild

• Case features stock bore, capable of accepting flywheels up to 8-1/2 inches in diameter

• Comes with cylinder studs, nickel-plated case bolts, crankcase fittings, and timing/magnetic drain plug for comprehensive assembly

• Manufactured in the USA with high-quality materials for durability and reliable performance

• Suggested to be used with S&S #12-8002 oil pump assembly for optimal engine operation

Fitment:
Harley Davidson FLST 1986
Harley Davidson FLST 1987
Harley Davidson FLST 1988
Harley Davidson FLST 1989
Harley Davidson FLST 1990
Harley Davidson FLST 1991
Harley Davidson FLT 1984
Harley Davidson FLT 1985
Harley Davidson FLT 1986
Harley Davidson FLT 1987
Harley Davidson FLT 1988
Harley Davidson FLT 1989
Harley Davidson FLT 1990
Harley Davidson FLT 1991
Harley Davidson FXR 1984
Harley Davidson FXR 1985
Harley Davidson FXR 1986
Harley Davidson FXR 1987
Harley Davidson FXR 1988
Harley Davidson FXR 1989
Harley Davidson FXR 1990
Harley Davidson FXR 1991
Harley Davidson FXST 1984
Harley Davidson FXST 1985
Harley Davidson FXST 1986
Harley Davidson FXST 1987
Harley Davidson FXST 1988
Harley Davidson FXST 1989
Harley Davidson FXST 1990
Harley Davidson FXST 1991