Kb Pistons Super Duty 4.125" Bore +.010 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.
Elevate your Milwaukee-Eight engine's performance with the Kb Pistons Super Duty Piston Set. These 4.125" bore, +.010 overbore pistons are engineered for 114 to 120 cubic inch builds, offering enhanced durability and a precise fit for your Harley-Davidson.
Why riders pick this
- Designed for Milwaukee-Eight 114 to 120 cubic inch engines
- 4.125" bore with +.010 overbore for rebuilds
- Anodized top ring groove and crown
- Line2Line abradable skirt coating for precise fit
- Includes premium Hastings rings, wrist pins, and locks
For riders looking to maximize their Milwaukee-Eight engine, the Kb Pistons Super Duty Piston Set provides a robust foundation. Designed for 114 to 120 cubic inch M8 builds, this set features a 4.125" bore with a +.010 overbore, perfect for freshening up cylinders or maximizing displacement. The advanced design promotes tight, quiet running clearances, essential for a long-lasting performance engine.
Precision Engineering for Power
- Anodized top ring groove and crown for superior wear resistance
- Line2Line abradable skirt coating ensures optimal, self-adjusting fitment
- Premium Hastings ring package for reliable sealing and reduced blow-by
- Forced wrist pin oiling for improved lubrication and component longevity
- Flat-top 1.2cc design with optimized compression height
Ready for Your Build
Each pair of Super Duty pistons comes complete with all necessary rings, wrist pins, and locks, simplifying your engine build process. These pistons are an ideal choice for riders seeking to improve the durability and power output of their Milwaukee-Eight Touring or Softail, especially when paired with a performance cam and a dyno tune.
Specifications
- Brand: KB Pistons
- Manufacturer Part #: KB542LCA.010
- Bore Size: 4.125"
- Overbore: +.010"
- Engine Size: 114cc to 120cc M8
- Compression Height: 1.083"
- Dish Volume: 1.2cc flat-top
- Length: 6 in
- Width: 5 in
- Height: 5 in
- Weight: 2.5 lbs
- Country of Origin: Mexico
Common questions
What is the overbore size of these pistons?
These Kb Pistons Super Duty pistons feature a +.010 overbore, designed for Milwaukee-Eight engines from 114 to 120 cubic inches with a 4.125" bore.
Are rings and pins included with the pistons?
Yes, this piston set comes as a complete pair, including premium Hastings rings, wrist pins, and locks for a straightforward installation.
Will these pistons work with my stock cylinders?
These pistons are a +.010 overbore size, meaning your cylinders will likely need to be bored out to match the larger diameter. Always confirm fitment with your engine builder.
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 | 824-01801 |
| WEIGHT | 2.5 lb |
