S&S Cycle 124″ Big Bore Kit For Harley Twin Cam 2006-2017
S&S 124″ Big Bore Kit: The Pinnacle of Twin Cam Displacement for 2026
The S&S Cycle 124″ Big Bore Kit for 2006-2017 Harley-Davidson Twin Cam models represents the 2026 pinnacle of heavy-duty engine architecture. For riders who refuse to settle for anything less than the largest bolt-on displacement possible, the 124″ kit is the definitive answer. By increasing the cylinder bore to 4.125″, S&S allows owners of 96″, 103″, and 110″ engines (with the standard 4-3/8″ stroke) to reach the massive 124ci threshold. This kit transforms the very DNA of your motorcycle, providing a level of secure, industrial-strength utility and acceleration that rivals purpose-built drag bikes. For the rider seeking a high-output 2026 presence and a displacement that defines the “hot rod” Harley-Davidson era, the S&S 124″ kit is the unmatched 2026 standard.
Forged Integrity and Thermal Management
What sets the S&S 124″ kit apart in the 2026 marketplace is the sophisticated engineering required to maintain a perfect ring seal at such a large bore diameter. The kit features forged aluminum pistons with a 10.8:1 compression ratio, offering a violent increase in throttle response while remaining manageable on 2026 premium pump fuels. These pistons are treated with advanced anti-friction coatings to ensure they can handle the high piston speeds of a 124ci engine during the intense heat of 2026 summer riding. The cylinders are constructed with high-tensile cast-in liners that resist the “ovaling” or warping often seen in lesser big bore kits. This structural rigidity is critical for maintaining peak cylinder pressure and ensuring the mechanical synchronization and longevity that professional engine builders demand.
S&S 124″ Twin Cam Big Bore Kit Technical Specifications
- Fitment: 2006 Dyna and 2007-2017 Twin Cam (Must have 4-3/8″ Stroke).
- Bore Size: 4.125″ Bore (Increases engine to 124ci).
- Compression Ratio: 10.8:1 (Optimized for 2026 high-performance street use).
- Pistons: Forged aluminum with precision-machined valve pockets.
- Installation: Requires crankcase machining for 4.125″ cylinder spigots.
- Gaskets: Includes premium S&S MLS (Multi-Layer Steel) head gaskets for a 2026 seal.
- Origin: 100% Designed, Cast, and Machined in the USA by S&S Cycle.
Expert Installation & Performance Advice
As specialists in extreme Twin Cam performance, we recommend the 124″ kit for riders who have already reinforced their bottom end. Pro Tip: To truly maximize 124 cubic inches, you must pair this kit with S&S Super Stock Heads and at least a 58mm throttle body to satisfy the engine’s massive air requirements. Installation Note: This kit requires crankcase machining to accept the larger 4.125″ cylinder spigots; we recommend a professional engine builder perform the 2026 case prep. Maintenance Note: Use a high-quality 20W-50 synthetic oil and ensure your 2026 oiling system is upgraded with a high-flow pump to manage the extra heat. Safety Note: A professional dyno tune via Dynojet Power Vision is mandatory to ensure the 124ci engine remains reliable and does not suffer from lean-out during your 2026 travels.
The Professional Standard for Twin Cam Extreme Performance
Choosing the S&S Cycle 124″ Big Bore Kit means investing in unmatched mechanical stability and a refined power signature. It offers a unique combination of modern metallurgical strength and a proven design that honors the performance legacy of the Harley-Davidson brand. For the rider who wants a high-output 2026 presence and a flawless engineering finish, the S&S 124″ Kit is the unmatched leader. Reach the peak of power, eliminate the limits, and ride the distance.
Features:
- The Big Bore kit yields excellent results with stock cylinder heads
- Cylinders are constructed from premium aluminum castings with cast-in iron liners
- Kits include cylinders, pistons, rings and gaskets (head, base and exhaust)
- Black finish
| Product Style | AmericanV-twin Item # | Catalog Number | Store Sku | MFR. Product # | Availability |
|---|---|---|---|---|---|
| S&S Cycle 124″ Big Bore Kit For Harley Twin Cam 2006-2017 | 82080 | RZ-82080 | 910-0338 | In Stock: Ships within 24 hours |
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