Cometic

Cometic specializes in multi-layer steel gaskets, which are often chosen for performance and big-bore builds. This page lists the Cometic range in the catalog for Harley-Davidson Big Twin, Sportster and V-Rod engines.

What Cometic makes

Milwaukee-Eight head gaskets come in 4.095 inch bore and .030 inch MLS thickness. Base gaskets use RC Gen2 embossing, and exhaust gaskets include a V-Rod multi-layer steel design. The range spans many bore sizes and thicknesses for Twin Cam and Evolution as well.

Why use MLS gaskets

Multi-layer steel gaskets hold their seal under higher cylinder pressure and are reusable in some cases, though they are normally replaced. Compression ratio changes with head gasket thickness, so thickness is a tuning variable as well as a sealing component.

Using the right one

Match engine family, bore size and thickness to your build. Clean and flatten the surfaces and torque the head fasteners as per your service manual. Plan the tune. Cometic parts for performance engines are sold for off-road and closed-course use only. See gaskets and seals, James Gaskets and piston kits for the full engine set.

Order head gaskets, base gaskets and exhaust gaskets together if you are doing a full top-end rebuild. Bore size is shown in inches in many titles, so compare to your cylinder bore measurements. Cometic gaskets for Twin Cam and Evolution engines come in a range of thicknesses, which gives builders another way to set compression.