✓ VERIFIED
Sep 26, 2019
Really nice kit great directions for install and ring gap. Follow the directions and you can't go wrong..
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S&S CYCLE
SKU: T14-852159
S&S Cycle 128 Cubic Inch Big Bore Cylinder & Piston Kit - Wrinkle Black for Harley Milwaukee-Eight
$1,643.95
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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.
Transform your 2017 and newer Harley Milwaukee-Eight 114 engine into a 128 cubic inch powerhouse with this S&S Cycle Big Bore Cylinder and Piston Kit. This comprehensive kit provides a substantial displacement upgrade without the need for crankcase machining.
Why riders pick this
- Upgrades 114 M8 to 128 cubic inches
- Bolt-on installation, no crankcase machining needed
- Includes forged pistons for durability
- Wrinkle black finish blends with factory components
- Comes with all gaskets and mounting hardware
Engineered for riders seeking a significant bump in performance, this S&S Cycle kit includes everything needed to take your M8 to the next level. The bolt-on design simplifies installation, allowing you to achieve a larger displacement and unlock serious power gains with precision-engineered forged pistons and cylinders.
Maximize Your M8's Potential
- Increases 114 cubic inch M8 engines to 128 cubic inches
- Features durable forged pistons with an optimized compression ratio
- Bolt-on installation means no machining required for your crankcases
- Wrinkle black finish without highlighted fins for a stealthy look
- Includes all necessary gaskets and mounting hardware for a complete install
Ready for Serious Riding
This big bore kit is designed for a direct fit on 2017 and newer Milwaukee-Eight models, offering a straightforward path to increased power and torque. While it's a bolt-on solution, a proper dyno tune is essential to maximize the performance benefits and ensure optimal engine operation after this significant displacement increase.
Specifications
- Brand: S&S Cycle
- Manufacturer Part #: 910-0685A
- Displacement Range: 114 to 128 cubic inches
- Compression Ratio: 11:1
- Piston Type: Forged
- Finish: Wrinkle black
- Weight: 29.56 lbs
- Category: Engine Components / Piston Sets - Powersports
Common questions
Will this kit fit my 2017+ M8 Harley?
Yes, this S&S Cycle big bore kit is specifically designed for 2017 and newer Harley-Davidson Milwaukee-Eight (M8) models.
Do I need to have my cylinders machined?
No, this is a bolt-on kit that requires no machining of your existing crankcases for installation.
What is included with this kit?
The kit includes forged pistons, cylinders in wrinkle black, all necessary gaskets, and mounting hardware for a complete installation.
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 | Piston Sets - Powersports |
| SKU | T14-852159 |
| WEIGHT | 29.56 lb |
Please contact us to confirm fitment for your specific motorcycle, or check the product title for compatibility notes.
CUSTOMER REVIEWS
4.88
8 RATINGS
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✓ VERIFIED
Apr 26, 2022
Excellent service and pricing im very satisfied
✓ VERIFIED
Sep 26, 2019
Better than OEM.. can't go wrong.
✓ VERIFIED
Mar 30, 2026
Very happy with this kit
Simple, easy kit.
✓ VERIFIED
Mar 29, 2026
SMS makes great aftermarket upgrades
✓ VERIFIED
Oct 24, 2025
👍👍 For fast delivery
Parts came just like as expected. They look great! Can't wait to install these bad boys along with a few other parts.