S&S Cycle Flywheels 4-1/2 in. Stroke, Performance Piston Weight - Harley-Davidson
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.
Build a rock-solid foundation for your high-performance Harley-Davidson engine with S&S Cycle Flywheels. Forged from heat-treated 4140 steel and meticulously balanced, these crankshaft assemblies are engineered to handle extreme power and sustained higher RPMs. They're designed for riders who demand maximum reliability and output from their V-twin.
Why riders pick this
- Heat-treated 4140 steel construction
- Designed for S&S Performance Pistons
- Balanced for 1213g piston weight
- Supports sustained higher RPM operation
- 4-1/2 inch stroke for 114 or 128ci builds
S&S Cycle has been setting the standard for V-twin performance for decades, and these flywheels continue that tradition. Designed with Finite Element Analysis, they eliminate weak spots and provide superior strength compared to stock components. The full-width wristpin design, paired with S&S Performance Pistons, creates an incredibly strong assembly that can withstand the rigors of aggressive riding and high-horsepower builds. This 4-1/2 inch stroke is ideal for 114 or 128 cubic inch engine projects.
Engineered for Extreme Performance
- Forged from heat-treated 4140 steel for exceptional strength
- Full-width wristpin design requires S&S Performance Pistons
- Balanced for 1213g piston weight to ensure smooth operation
- Capable of handling sustained higher RPM without crankpin welding
- Precision-machined with pre-installed balance gear
Building a High-Output V-Twin
These S&S Cycle flywheels are the cornerstone of a serious performance engine build. Their robust construction and precision balancing provide the stability needed for increased displacement and higher RPMs. Because of the full-width wristpin design, it is essential to pair these flywheels with S&S Performance Pistons for proper fitment and optimal results. Always confirm compatibility with your specific engine displacement and desired build specifications before ordering.
Specifications
- Brand: S&S Cycle
- Manufacturer Part #: 320-0603
- Weight: 42.7 lb
- Category: Drivetrain / Flywheels
Common questions
Do I need S&S pistons to use these flywheels?
Yes, the full-width wristpin design of these flywheels requires the use of S&S Performance Pistons for correct fitment and optimal performance.
Are these flywheels suitable for a stock engine rebuild?
These flywheels are primarily designed for high-performance applications and require specific S&S Performance Pistons. For stock rebuilds, S&S offers other flywheel options. Please confirm your build goals.
What stroke length do these flywheels have?
These flywheels feature a 4-1/2 inch stroke, making them suitable for 114 or 128 cubic inch engine builds.
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 | Flywheels |
| SKU | T14-662047 |
| WEIGHT | 42.7 lb |
