What does 'machined' mean for this cylinder head?

Machined means the surfaces of the head that mate with the cylinder and the cylinder head gasket have been precisely cut and smoothed using machine tools. This ensures a perfectly flat and true surface for a leak-free seal and optimal engine performance.

What is the significance of the 4-1/8 inch bore size?

The 4-1/8 inch bore diameter specifies the size of the cylinder this head is designed to fit. It's a critical measurement for ensuring the combustion chamber volume is correct for your engine's configuration and for achieving proper compression.

Why is this part not CARB approved?

CARB (California Air Resources Board) approval relates to emissions standards. Parts that are not CARB approved have not met these specific emissions requirements and therefore cannot be legally sold or installed on vehicles in California.

S&S Cycle Front Head 4-1/8in Bore Black 90-1158FA

Name: S&S Cycle 84-99 BT 4-1/8in Bore Front Head
Brand: S&S Cycle
SKU: s-s-cycle-s-s-cycle-84-99-bt-4-1-8in-bore-front-head-t14-664020
Price: 701.25 USD
Availability: BackOrder

S&S Cycle 84-99 BT 4-1/8in Bore Front Head

$701.25

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 84-99 BT 4-1/8in Bore Front Head. Machined for precise fitment.

Key Features

Fits 1984-1999 Big Twin (BT) engines.
Features a 4-1/8 inch bore diameter.
Precision machined for a flat and true mating surface.
Finished in black for a custom engine appearance.
Not CARB approved; cannot ship to California.

This part is designed for 1984-1999 Big Twin (BT) engine models. Please verify compatibility with your specific vehicle's engine configuration.

Secure CheckoutFast Shipping631-982-0042

Product Details

Starting with a 4-1/8 inch bore diameter, this front cylinder head from S&S Cycle is precision machined for 1984-1999 Big Twin (BT) engines. The machining process ensures that the critical mating surfaces are perfectly flat and true, which is essential for a proper seal and optimal engine performance. This head is finished in black, giving your engine a clean, custom look that stands out.

S&S Cycle is well-known for its commitment to quality and performance in the V-twin world. This front head is built to meet those standards, offering a solid option for those rebuilding or upgrading their engine's top end. The precise machining means you can expect a good fit during installation, reducing the chances of leaks or other issues down the road. It's designed to work with the specific bore size of your Big Twin engine, ensuring compatibility and proper combustion chamber volume.

When undertaking an engine build of this nature, it's important to have all the necessary components ready. While this head is a key piece, remember to consult your service manual for any specific installation procedures or additional parts that may be required to complete your engine overhaul. Please note that this part is not CARB approved and cannot be shipped to California.