Kb Pistons Super Duty 4.250" Bore M8 107-124" 11.8:1 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 designed to elevate the performance of Harley-Davidson Milwaukee-Eight engines, specifically for 107 to 124 cubic inch builds. This 4.250" bore, 11.8:1 compression standard size kit provides a robust foundation for increased power and reliability.
Why riders pick this
- Designed for Harley Milwaukee-Eight 107-124 cubic inch engines
- 4.250" bore with 11.8:1 compression ratio
- Anodized crown and top ring groove for extreme durability
- Abradable skirt coating for tight, quiet operation
- Includes premium rings, wrist pins, and locks
- Accommodates 1mm oversize valves
For riders looking to push their Milwaukee-Eight engine harder, these KB Super Duty pistons offer the high compression and durable construction needed. Crafted with advanced features, they are built to endure the stresses of aggressive riding while maintaining smooth, quiet operation. This standard bore kit is a direct fit for many M8 107-124 cubic inch projects.
High-Performance Features for M8 Engines
- Anodized crown and top ring groove for superior durability
- Line2Line Abradable skirt coating for optimal running clearance and quiet function
- Premium Hastings 1.2mm Steel Nitride top ring and Ductile Napier second ring package
- Forced wrist pin oiling for enhanced lubrication and extended component life
- Flat-top design with valve pockets that accommodate 1mm oversize valves
Unlock Your Engine's Potential
This piston kit is an essential upgrade for any Milwaukee-Eight performance build. The comprehensive kit includes pistons, premium rings, wrist pins, and locks, ensuring a complete and straightforward installation. Achieve a higher compression ratio for more responsive power, making your M8 a true force on the road or track.
Specifications
- Brand: KB Pistons
- Manufacturer Part #: KB595LCA.STD
- UPC: 800745276155
- Engine: Milwaukee-Eight (M8)
- Bore: 4.250"
- Compression Ratio: 11.8:1
- Compression Height: 1.083"
- Piston Dish: 1.2cc flat-top
- Weight: 2.5 lbs per pair
- Country of Origin: Mexico
Common questions
What compression ratio do these pistons provide?
These KB Pistons Super Duty pistons offer an 11.8:1 compression ratio, ideal for performance-oriented Milwaukee-Eight engine builds.
Are these pistons a direct fit for a stock bore M8 engine?
Yes, this is a standard size piston kit, designed to fit Harley-Davidson Milwaukee-Eight (M8) engines with a 4.250" bore without requiring an overbore.
What components are included with this piston kit?
The kit includes a pair of pistons, premium Hastings rings, stainless steel wrist pins, and round wire locks for a complete top-end upgrade.
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 | 824-01832 |
| WEIGHT | 2.5 lb |
| 11.8 | 1 Compression |
