S&S Cycle MK-Series B Crankcases - Harley Softail Big Twin
About S&S Cycle
S&S Cycle has built American V-twin performance parts in Viola, Wisconsin since 1958 — flywheels, carburetors, cams, cylinder heads and complete crate engines. When a Harley owner talks about a 124, a 128 or a 131 build, they are usually talking about S&S. Few names carry more weight with engine builders in this space.
S&S Cycle MK-Series B crankcases are engineered for Harley-Davidson Softail models, providing a robust foundation for high-performance V-twin engine builds. These crankcases support big-displacement setups without requiring frame modifications.
Why riders pick this
- Supports large-displacement builds up to 136 cubic inches
- Improved oil scavenging for better engine health
- Large-volume sump design fits stock Softail frames
- No frame modification required for installation
- Ideal for high-performance Softail engine projects
When you're pushing the limits with a big-inch Softail build, a strong foundation is critical. S&S Cycle MK-Series B crankcases are designed to meet those demands, capable of supporting builds up to 136 cubic inches. They feature improved oil scavenging and a large-volume sump, all while fitting directly into a stock Softail frame, making them an ideal choice for serious engine upgrades.
Built for Big-Displacement Power
- Supports cylinder kits and stroker cranks for up to 136 cubic inches
- Improved oil scavenging system enhances engine lubrication
- Large-volume sump design for better oil management
- Engineered to fit stock Softail frames without modification
The Core of a Performance Build
These S&S Cycle crankcases are more than just a replacement part; they are the heart of a performance V-twin. Their design allows for significant power increases while maintaining the integrity of your Softail chassis. If you're planning a serious engine upgrade, these crankcases provide the strength and capacity needed for reliable, high-horsepower operation.
Specifications
- Brand: S&S Cycle
- Manufacturer Part #: 310-1326
- Category: Engine Components / Crankshafts
- Weight: 49.2 lb
Common questions
What is the maximum displacement these crankcases can support?
These S&S Cycle MK-Series B crankcases are designed to support big-displacement builds up to 136 cubic inches, making them suitable for serious performance upgrades.
Do I need to modify my Softail frame to install these crankcases?
No, these crankcases are specifically engineered to fit into a stock Harley-Davidson Softail frame without requiring any modifications to the frame.
Can these crankcases be used with a stock crankshaft?
While designed for performance builds, it's best to verify compatibility with your specific S&S Cycle components and build plan before ordering. Consult your engine builder for guidance on pairing with a stock crank.
Ordering from Vtwinbikers
- Brand new, sourced through authorized US distribution — never used, never grey-market.
- Not sure it fits? Use Shop by Bike to filter by your year and model, or email us and we will confirm before you order.
- Harley-Davidson and Indian Motorcycle is all we do, so you are talking to people who ride what you ride.
| BRAND | S&S Cycle |
| TYPE | Crankshafts |
| SKU | T14-803042 |
| WEIGHT | 49.2 lb |
