✓ VERIFIED
Sep 26, 2019
Really nice kit great directions for install and ring gap. Follow the directions and you can't go wrong..
Image coming soon
S&S CYCLE
SKU: T14-852154
S&S Cycle 124" Big Bore Cylinder & Piston Kit - Harley 107 M8 Touring
$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.
The S&S Cycle big-bore cylinder and piston kit is engineered to transform your 2017+ Harley-Davidson 107 cubic-inch Milwaukee-Eight Touring engine into a potent 124 cubic-inch powerhouse. This kit provides a significant displacement increase with a straightforward bolt-on installation.
Why riders pick this
- Transforms 107ci M8 to 124ci displacement
- Forged pistons with 11:1 compression ratio
- Bolt-on installation, no machining required
- Includes all gaskets and mounting hardware
- Designed for 2017+ Harley Touring models (107ci)
- Significant power and torque increase
Unleash the full potential of your Milwaukee-Eight Touring model with the S&S Cycle 124" Big Bore Kit. This upgrade takes your 107 cubic-inch engine to a commanding 124 cubic inches, delivering a substantial boost in power and torque. Featuring high-quality forged pistons with an 11:1 compression ratio, this kit is designed for performance enthusiasts who demand more from their Harley-Davidson. Best of all, it's a true bolt-on solution, including all necessary gaskets and hardware, eliminating the need for complex machining.
Uncork Serious Milwaukee-Eight Power
- Upgrades 107 cubic-inch M8 engines to 124 cubic inches
- Features forged pistons with an 11:1 compression ratio
- True bolt-on installation requires no machining
- Includes all necessary gaskets and mounting hardware
- Designed for 2017 and newer Harley-Davidson Touring models
Ready for the Road Ahead
This S&S Cycle big-bore kit is more than just a displacement increase; it's a comprehensive performance upgrade. The carefully matched cylinders and pistons work together to create a more efficient and powerful engine. While this kit is a bolt-on, a proper dyno tune will ensure optimal performance and reliability after installation, allowing you to fully experience the newfound power on your Harley Touring bike.
Specifications
- Brand: S&S Cycle
- Manufacturer Part #: 910-0625A
- Bore × Stroke: 4.250 in × 4.375 in
- Displacement Upgrade: 107 to 124 cubic inches
- Compression Ratio: 11:1
- Weight: 30.6 lb
- Category: Engine Components / Piston Sets - Powersports
Common questions
What is included in this S&S Cycle 124" Big Bore Kit?
The kit includes new cylinders, forged pistons, piston rings, all necessary gaskets, and mounting hardware for a complete bolt-on installation.
Do I need to have my cylinder heads machined or ported for this kit?
No, this S&S Cycle big-bore kit is designed for true bolt-on installation and does not require any machining or porting of your cylinder heads.
Is this kit compatible with Harley-Davidson Tri-Glide or three-wheel models?
No, this S&S Cycle 124" Big Bore Cylinder and Piston Kit is not recommended for Tri-Glide or other three-wheel Harley-Davidson models.
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 | T14-852154 |
| WEIGHT | 30.6 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.