The ornamental design for a portion of a motorcycle cylinder head, as shown and described.

An engine component comprising:</claim-text> at least one thermally conductive cooling fin structure, the cooling fin structure including a first surface, an oppositely facing second surface, and an edge surface in communication with the first ce and the second surface; and at least a portion of the edge surface of the fin structure including at least one intagliated region comprising at least two concavities of a preselected configuration therein, said edge surface defining a longitudinal axis and one of said concavities defining a longitudinal axis, said longitudinal axis of said one of said concavities being oriented at an angle to said longitudinal axis of said edge surface. view more

The engine component of claim 1, wherein at least one of the concavities is an elongated concavity.

The engine component of claim 1, wherein at least one intagliated region comprises at least one first, upper elongated concavity and at least one second, lower elongated concavity.

The engine component of claim 3, wherein at least one of said concavities defines a central region and at least one end region, said central region having a depth, as determined from said edge surface, which is dimensionally larger than a depth defined by said end region as determined from said edge surface. view more

The engine component of claim 1, further comprising:</claim-text> a majority of the edge surface of the fin structure defines concavities therein.

The engine component of claim 1, wherein the engine component is selected from the group consisting of a engine casing, a cylinder, a cylinder head, an engine component cover, a rocker arm cover, a cam cover, an inspection cover, an access cover, an oil cooler, a tube and shell heat exchanger. view more

The engine component of claim 1, wherein said longitudinal axis of said one of said concavities being oriented at an angle to said longitudinal axis of said edge surface comprises said longitudinal axis of said one of said concavities being oriented at an acute angle to said longitudinal axis of said edge surface. view more

The engine component of claim 1 wherein said engine component is selected from the group consisting of aluminum, aluminum based alloy, iron, titanium, tungsten and steel.

An engine component comprising:</claim-text> at least one thermally conductive cooling fin structure, the cooling fin structure including a first surface, an oppositely facing second surface, and an edge surface in communication with the first ce and the second surface; and at least a portion of the edge surface of the fin structure including at least one intagliated region, such that an intersection of said first surface and said edge surface defines a scalloped configuration. view more

The engine component of claim 9 wherein said component is selected from the following group consisting of a cylinder, cover, cooler, plate and head.

The engine component of claim 9 wherein said component is selected from the following group consisting of aluminum, aluminum based alloy, iron, titanium, tungsten or steel.

A method of producing an irregular surface on a engine component comprising:</claim-text> providing a vehicle engine having a least one exposed component; providing a plurality of fins on said engine component; and engraving a portion of an edge of fin on said engine component with an engraving tool to define a plurality of elongate concavities within a surface of said edge, wherein each said concavity defines a longitudinal axis and said longitudinal axes are oriented parallel to one another, such that said portion of an edged of said fin defines a sculpted surface, a multi-faceted surface, a scalloped surface, a concave surface, an overlapping structural relief, a relieved surface, a cut surface, a rounded surface, a fluted surface, a pattern of inequalities or a textured surface. view more

The method according to claim 12 wherein said component is selected from the following group consisting of a cylinder, cover, cooler, plate and head.

The method according to claim 12 wherein said engine component is selected from the following group consisting of aluminum, aluminum based alloy, iron, titanium, tungsten or steel.