✓ VERIFIED
Jun 21, 2017
product is shipped without crankcase ventilation parts that are clearly part of kit.
S&S CYCLE
SKU: T14-662687
S&S Cycle 1250cc Big Bore Conversion Kit - Harley Sportster
$3.126.000,00
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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.
Unleash significant power gains in your Harley Sportster with the S&S Cycle 1250cc Big Bore Conversion Kit. This comprehensive kit transforms 883cc or 1200cc engines into a potent 1250cc powerplant, delivering a noticeable boost in torque and horsepower without requiring complex machine work.
Why riders pick this
- Converts 883cc/1200cc to 1250cc displacement
- Forged pistons with coated skirts for durability
- Includes S&S cylinders and complete gasket set
- No machine work or rebalancing needed
- Direct bolt-on performance upgrade
The S&S Cycle 1250cc Conversion Kit is engineered for Sportster riders seeking a substantial performance upgrade. Designed as a direct bolt-on solution, this kit allows you to increase your engine's displacement to 1250cc, providing a dramatic improvement in acceleration and overall power. The included forged pistons with coated skirts and S&S cylinders are precision-matched, ensuring optimal performance and durability right out of the box.
Bolt-On Power Upgrade
- Converts 883cc or 1200cc Sportster engines to 1250cc
- Forged 5cc pop-up pistons with durable coated skirts
- S&S 3-9/16" bore cylinders for increased displacement
- Complete gasket set included for a sealed assembly
- No machining or rebalancing required for installation
Ready for the Road
This kit simplifies the big bore conversion process by eliminating the need for costly and time-consuming machine work or piston rebalancing. Everything required for the upgrade, including cylinders, pistons, and a full gasket set, is provided. While the kit is designed for straightforward installation, a proper dyno tune is highly recommended after installation to optimize fuel mapping and maximize your Sportster's newfound power and ensure reliable operation.
Specifications
- Brand: S&S Cycle
- Manufacturer Part #: 910-0692
- Displacement Increase: 883cc or 1200cc to 1250cc
- Piston Bore: 3-9/16"
- Weight: 22.75 lb
- Category: Engine Components / Piston Sets - Powersports
Common questions
Does this kit require machine work or piston balancing?
No, this S&S Cycle 1250cc conversion kit is engineered for direct installation without requiring any machining of your cases or rebalancing of the pistons.
Can I use my stock 883 cylinder heads with this kit?
No, 883 cylinder heads are not compatible with this 1250cc conversion kit and must be replaced with 1200cc or aftermarket heads.
Will I need to tune my bike after installing this kit?
Yes, any significant engine modification like a big bore conversion will require a proper dyno tune or EFI recalibration to ensure correct air/fuel ratios and optimal performance.
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 | T14-662687 |
| WEIGHT | 22.75 lb |
Please contact us to confirm fitment for your specific motorcycle, or check the product title for compatibility notes.
CUSTOMER REVIEWS
4.5
8 RATINGS
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✓ VERIFIED
Nov 6, 2025
After much fabrication and alternative parts, it is installed. Not having a manifold ported for a map sensor complicates things significantly. I wasn’t going to settle for some pro rated refund because it was out of box. Much work left to do, but I’m committed to making it work.
✓ VERIFIED
Aug 5, 2022
Havent put it on yet but if its as good as the customer service i recieved getting the carb itll be breezy!
✓ VERIFIED
Apr 8, 2021
Fast shipping and it is in stalled runs great
✓ VERIFIED
Dec 3, 2020
Carb was installed per the O.E.M. Instructions, set-up and it runs and performs better than new! The JP Cycle online order was perfect!
✓ VERIFIED
Sep 14, 2020
I love the upgraded carburetor and intake system S&S .. great product and great addition too my harley.
