Kb Pistons Super Duty 4.125" Bore Flat-Top Piston Set - Harley Milwaukee-Eight 114 to 120
About Kb Pistons
KB Performance Pistons builds hypereutectic and forged pistons for American V-twin engines, and is a long-standing choice for big-bore and stock-replacement rebuilds where budget and durability both matter.
Unleash the full potential of your Milwaukee-Eight engine with the Kb Pistons Super Duty Piston Set. Engineered for 114 to 120 cubic inch builds, these 4.125" bore pistons deliver reliable performance for your Harley-Davidson.
Why riders pick this
- Designed for Milwaukee-Eight 114 to 120 cubic inch engines
- 4.125" bore with 1.2cc flat-top piston design
- Anodized top ring groove and crown for durability
- Line2Line abradable skirt coating for tight clearances
- Includes premium Hastings rings, wrist pins, and locks
When you're pushing the limits of your Milwaukee-Eight, you need components that can keep up. The Kb Pistons Super Duty Piston Set is designed for M8 114 to 120 cubic inch engines, providing the strength and precision required for high-performance builds. These pistons feature a 4.125" bore and a 1.2cc flat-top design, optimized for tight clearances and quiet operation.
Engineered for Durability and Performance
- Anodized top ring groove and crown for increased wear resistance
- Line2Line abradable skirt coating ensures a precise, self-honing fit
- Premium Hastings ring package for superior sealing and longevity
- Forced wrist pin oiling enhances lubrication and reduces friction
- Valve pockets accommodate 1mm oversize valves for broader compatibility
Build with Confidence
Whether you're doing a routine rebuild or chasing more power, these Super Duty pistons are a solid foundation. They come complete with all necessary rings, wrist pins, and locks, making installation straightforward. Pair them with a performance cam and a proper tune for a significant upgrade in your V-twin's output and reliability.
Specifications
- Brand: KB Pistons
- Manufacturer Part #: KB542LCA.STD
- Bore: 4.125 in
- Engine: M8 (114-120 cu in)
- Design: Flat-top, 1.2cc
- Compression Height: 1.083 in
- Quantity: Pair
- Length: 6 in
- Width: 5 in
- Height: 5 in
- Weight: 2.5 lbs
- Country of Origin: Mexico
Common questions
What engine sizes are these pistons compatible with?
These Kb Pistons Super Duty pistons are designed for Harley-Davidson Milwaukee-Eight engines ranging from 114 to 120 cubic inches, with a 4.125" bore.
Do these pistons require a special ring set?
No, this piston set includes a premium Hastings ring package, along with wrist pins and locks, providing a complete assembly ready for installation.
Will these pistons affect my engine's compression ratio?
These pistons feature a 1.2cc flat-top design. For specific compression ratio outcomes with your cylinder head and build, consult a professional or use a compression calculator.
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 | Kb Pistons |
| TYPE | Piston kits & Components |
| SKU | 824-01800 |
| WEIGHT | 2.5 lb |
