Kb Pistons Super Duty 4.250" Bore M8 107-124" 11.4:1 Standard Piston Kit - Harley Milwaukee-Eight
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.
The KB Pistons Super Duty piston kit is engineered for Harley-Davidson Milwaukee-Eight engines, offering a significant upgrade for 107 to 124 cubic inch builds. This 4.250" bore, 11.4:1 compression standard size kit is built to enhance durability and performance.
Why riders pick this
- Designed for Harley Milwaukee-Eight 107-124 cubic inch engines
- 4.250" bore with 11.4:1 compression ratio
- Anodized crown and top ring groove for durability
- Abradable skirt coating for tight, quiet running clearance
- Includes premium rings, wrist pins, and locks
- Accommodates 1mm oversize valves
When you're building out a Milwaukee-Eight engine, reliable, high-performance internals are non-negotiable. These KB Super Duty pistons are crafted with advanced features to withstand the demands of increased power and ensure a long, quiet service life. They're designed for a standard bore application, making them a direct fit for many M8 107-124 cubic inch projects.
Engineered for Milwaukee-Eight Performance
- Anodized crown and top ring groove for enhanced durability
- Line2Line Abradable skirt coating ensures tight running clearances and quiet operation
- Premium Hastings Steel Nitride top ring and Ductile Napier second ring package
- Forced wrist pin oiling for improved lubrication and longevity
- Flat-top design with valve pockets accommodating 1mm oversize valves
Build with Confidence
This piston kit provides a solid foundation for your Milwaukee-Eight performance build. The included rings, wrist pins, and locks mean you have a complete solution ready for assembly. Whether you're refreshing an engine or pushing for more displacement, these Super Duty pistons deliver the robust construction needed for aggressive riding and sustained power.
Specifications
- Brand: KB Pistons
- Manufacturer Part #: KB576LCA.STD
- UPC: 800745266941
- Bore: 4.250"
- Compression Ratio: 11.4:1
- Displacement: 1.2cc
- Compression Height: 1.083"
- Weight: 2.5 lbs
- Country of Origin: Mexico
- Quantity: Pair
Common questions
What Milwaukee-Eight engine sizes do these pistons fit?
These KB Pistons Super Duty pistons are designed for Harley-Davidson Milwaukee-Eight engines ranging from 107 to 124 cubic inches, in a standard bore size.
Do these pistons come with all necessary components for installation?
Yes, this kit includes a pair of pistons along with premium rings, wrist pins, and round wire locks, providing a complete package for your engine build.
What is the compression ratio of these pistons?
These pistons feature an 11.4:1 compression ratio, optimized for performance applications in Milwaukee-Eight engines.
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 | 824-01830 |
| WEIGHT | 2.5 lb |
| 11.4 | 1 Compression |
