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.
Reinforce your 2006-2017 Harley-Davidson Dyna with the S&S Cycle 4-1/8" bore crankcase. Machined from robust 356-T6 aircraft-grade aluminum, this crankcase features thicker wall sections for superior strength and durability. It provides a solid foundation for both stock replacement and custom high-performance engine builds, ready to handle serious power.
Why riders pick this
- 4-1/8" bore for stock or custom builds
- Machined from 356-T6 aircraft-grade aluminum
- Timken sprocket shaft bearing for extreme duty
- Clearanced for large strokes and high-lift cams
- Pre-installed studs and cam bearings
The S&S Cycle crankcase for 2006-2017 Dyna models is engineered for riders who demand uncompromising strength and precision from their V-twin engine. Its construction from aircraft-grade aluminum with reinforced sections ensures it can withstand the rigors of aggressive riding and high-output engine configurations. This crankcase comes ready for assembly with pre-installed studs and cam bearings, streamlining your build process.
Built for Extreme Duty and Performance
- Machined from durable 356-T6 aircraft-grade aluminum
- Thicker wall sections provide enhanced strength and rigidity
- Timken sprocket shaft bearing rated for extreme duty applications
- Clearanced for strokes up to 4 13/16" and cams up to .720" lift
- Pre-installed studs and cam bearings for easier assembly
- Reinforced front motor mount for improved stability
The Ultimate Foundation for Your Dyna Engine
Whether you're performing a stock bore replacement or embarking on an ambitious custom engine build, this S&S crankcase provides the robust core you need. Its generous clearances for stroke and cam lift allow for a wide range of performance upgrades, making it an ideal choice for big-inch projects. The tough powder coat finish adds to its durability and provides a clean, factory-style appearance. For optimal installation, this crankcase is designed to work seamlessly with S&S oil line installation kits.
Specifications
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Brand: S&S Cycle
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Manufacturer Part #: 310-0856
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Bore Size: 4 1/8" (stock replacement)
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Weight: 36.35 lb
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Material: 356-T6 aircraft-grade aluminum
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Category: Engine Components / Crankshafts
Common questions
Will this crankcase fit my 2018 or newer Dyna model?
No, this S&S Cycle crankcase is specifically engineered for 2006-2017 Harley-Davidson Dyna models and is not compatible with 2018 or newer models.
What kind of engine builds is this crankcase suitable for?
This crankcase is suitable for both stock bore replacement applications and as a robust foundation for custom engine builds, including those using S&S T111, T124, or T144 applications.
Are any bearings or studs included with the crankcase?
Yes, this S&S Cycle crankcase comes with studs and cam bearings pre-installed. The pinion and Timken bearing are also included, simplifying the assembly process.
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.
