For a motorcycle build targeting 103 to 124 cubic inches, the S&S 124-inch kit is the closest listed match, while the S&S 107-inch kit may suit a smaller-displacement goal. The other listings are for different displacements or motorcycle applications, so buyers should confirm engine fitment before ordering. The comparison below highlights what each listing says and where its stated application differs from a 103-to-124-inch build.
| Product | Stated displacement or application | Best suited for |
|---|---|---|
| S&S 124-inch kit | 124 cubic inches | Buyers seeking the upper end of the target range |
| S&S 107-inch kit | 107 cubic inches | Buyers seeking a lower target displacement |
| S&S 96-inch kit | 96 cubic inches | Buyers whose build calls for 96 cubic inches |
| Cylinder Works kit | 270cc; Suzuki RM-Z 250, 2007–2009 | Owners of the listed Suzuki application |
| 57mm bore kit | Upgrade to 150cc; listed small-bike models | Owners of the named 125/135 models |
S&S Cycle 124-Inch Cylinder Kit
This kit is the most direct match for a build targeting 124 cubic inches. Its listed feature says the big-bore kit can yield results with stock cylinder heads. That makes it a possible choice for buyers planning to retain stock heads, subject to confirming that the kit matches the exact engine and configuration.
Best for: Riders whose target displacement is 124 cubic inches and whose engine is confirmed compatible. Why it was selected: Its stated displacement sits at the top of the requested 103-to-124 range.
Limitation: The feature explicitly says it is not for Twin Cooled motors. Do not choose it for that setup, and verify fitment details before purchase.
S&S Cycle 107-Inch Big Bore Kit
The listing identifies this as an S&S Cycle 107-inch big-bore kit. Its displacement is within the requested 103-to-124 range, but below the 124-inch option. Buyers should compare the target displacement for their build with the exact engine application rather than treating 107 and 124 cubic inches as interchangeable.
Best for: Buyers planning a 107-cubic-inch build. Why it was selected: It is one of the supplied kits with a stated displacement inside the requested range.
Limitation: The provided product information supplies no further fitment or included-component details. Confirm the application and contents with the seller or manufacturer before ordering.
S&S Cycle 96-Inch Big Bore Kit
This black powder-coat kit is listed as a 96-inch kit, so it does not meet a 103-to-124-inch displacement target. Its supplied features say installation does not require boring or splitting existing cases: the cylinders are swapped. The kit includes cylinders, pistons, rings, and head, base, and exhaust gaskets.
Best for: Buyers whose verified build calls for the listed 96-inch displacement. Why it was selected: It is a related S&S big-bore option, and its included parts and installation notes are specifically described.
Limitation: It is below the requested displacement range. Its case-installation note does not establish compatibility with a particular motorcycle, so confirm fitment.
Cylinder Works 270cc Cylinder Kit
This kit is for a different class of motorcycle engine, not a 103-to-124-cubic-inch build. Listed specifications include a 270cc displacement, 80mm cylinder diameter, and 13.4:1 compression ratio. The package includes a cylinder, piston kit, and top-end gasket kit. The stated application is the Suzuki RM-Z 250 from 2007 through 2009.
Best for: Owners of the listed Suzuki RM-Z 250 years seeking the specified 270cc kit. Why it was selected: Its application and included components are clearly stated, which helps distinguish it from large-displacement kits.
Limitation: Its displacement and stated fitment do not match the requested 103-to-124 cubic-inch category. Avoid it for that type of build.
57mm Bore Kit For TNT Models
This listing describes a 57mm bore kit that upgrades displacement to 150cc. It names BJ125-3E, TNT125, TNT135, and other 154FMI-7 applications. The listed benefits include improved throttle response and the potential for further modifications, such as upgraded systems or carburetors.
Best for: Owners of a specifically listed small-displacement model seeking the stated 150cc upgrade. Why it was selected: Its named applications and displacement make clear that it serves a different motorcycle segment.
Limitation: It is not a 103-to-124-cubic-inch kit. Confirm the exact model and engine code before considering it.
Buying Guide: How To Choose A Big Bore Kit
What displacement should you choose?
Start with the target displacement for the engine build. Of these listings, the 107-inch and 124-inch kits fall within the requested 103-to-124 range. The 96-inch kit is below it, while the 270cc and 150cc options are for much smaller engines. Check the units carefully: cubic inches and cubic centimeters describe different displacement scales.
How can you verify fitment?
Match the kit to the motorcycle’s exact year, model, engine, and cooling configuration. A stated displacement alone does not prove that a kit fits. The 124-inch listing specifically excludes Twin Cooled motors, and the Cylinder Works and 57mm kits name their own applications. Ask the seller or manufacturer to confirm fitment if the supplied details do not cover your setup.
What should you check in the kit contents?
Review which parts are included before comparing options. The 96-inch kit lists cylinders, pistons, rings, and several gaskets. The Cylinder Works kit lists a cylinder, piston kit, and top-end gasket kit. The supplied details for the 107-inch and 124-inch kits do not specify complete contents, so verify what additional parts may be needed.
Do stock heads or case work affect the decision?
The 124-inch listing says it can work with stock cylinder heads, with the Twin Cooled exclusion noted above. The 96-inch listing says its cylinder swap does not require boring or splitting existing cases. Treat these as product-specific statements, not guarantees for every engine. Confirm whether your build needs machining or other changes with a qualified mechanic.
Frequently Asked Questions
Which listed kit is closest to a 124-inch build?
The S&S Cycle 124-inch cylinder kit is the direct displacement match. Its listing excludes Twin Cooled motors.
Is the 107-inch kit within the 103-to-124 range?
Yes. Its stated 107-inch displacement is within that range, although it is smaller than the 124-inch option.
Does the 96-inch kit meet the target range?
No. The listing identifies it as a 96-inch kit, which is below 103 cubic inches.
Are the 270cc and 150cc kits alternatives for a 124-inch engine?
No. Their stated displacements and applications are for different motorcycle engine categories. Confirm application rather than relying on the phrase “big bore.”
What should I confirm before ordering?
Verify exact engine fitment, cooling configuration, included parts, and any required machining or additional components.