What is the primary advantage of the 4-1/8 inch bore on this crankcase?

The 4-1/8 inch bore is designed to accommodate larger pistons, allowing for significantly increased engine displacement. This is crucial for builders aiming to create custom, high-performance engines with greater power potential.

Can I use my existing transmission with this S&S Cycle crankcase?

Yes, the rear motor mount on these stock-style crankcases bolts directly to the stock 1999-2006 transmission for most models, except for the 2006 HD Dyna. This ensures compatibility with your existing drivetrain components.

Specifications

Brand: S&S Cycle
Part #: 106-4043A
UPC: 106-4043A

S&S Cycle 99-06 BT 4-18in Bore Crankcase - Silver

Name: S&S Cycle 99-06 BT 4-18in Bore Crankcase - Silver
Brand: S&S Cycle
SKU: s-s-cycle-s-s-cycle-99-06-bt-4-18in-bore-crankcase-silver-t14-663803
Price: 2178.64 USD
Availability: BackOrder

$2178.64

On Backorder

Order now to reserve yours — we'll ship as soon as stock arrives. Full refund if we're unable to fulfill.

S&S Cycle 99-06 BT 4-18in Bore Crankcase - Silver. Built for HD Twin Cam 88 engines, this crankcase allows for larger displacement builds.

Key Features

Fits HD Twin Cam 88 engines in 1999-2006 HD chassis.
Features a 4-1/8 inch bore for custom, large displacement engine builds.
Compatible with stock primary, charging system, and other stock components.
Available with S&S cylinder stud pattern or stock cylinder stud pattern.
Ideal for use with S&S 124" Hot Set Up Kit for stock crankcases when using stock stud pattern.
Not compatible with HD Twin Cam 88B or 2007-2016 HD Twin Cam 96/96B engines.

This crankcase is designed for HD Twin Cam 88 engines in 1999-2006 HD chassis, excluding 2006 HD Dyna models. It is not compatible with HD Twin Cam 88B or 2007-2016 HD Twin Cam 96/96B engines.

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About this part

Product Details

S&S Cycle is well-known for building high-performance engine components for Harley-Davidson motorcycles. This crankcase is a prime example, designed specifically to replace the stock crankcases in HD Twin Cam 88 engines found in 1999-2006 HD chassis. It's built to work with your existing stock primary, charging system, and other original components, making it a straightforward replacement for your engine's foundation.

This particular crankcase features a 4-1/8 inch bore, which is ideal for builders looking to create significantly larger displacement custom engines. You can even choose between the S&S cylinder stud pattern or the stock cylinder stud pattern. The 4-1/8 inch bore cases with the stock stud pattern are a perfect match for the S&S 124" Hot Set Up Kit designed for stock crankcases, opening up serious possibilities for increased power and torque. Keep in mind that these crankcases are not compatible with HD Twin Cam 88B, or 2007-2016 HD Twin Cam 96 or 96B engines.

When undertaking a significant engine build, starting with a solid crankcase is essential. This S&S Cycle crankcase offers the foundation for a powerful, custom engine, allowing you to push the boundaries of displacement and performance. Please note that this part is not CARB approved and cannot be shipped to California.