The ornamental design for a motorcycle fork, as and described.
FIG. 1 is a perspective view of a motorcycle fork in accordance with the invention.
FIG. 2 is a front elevation view of the motorcycle fork shown in FIG. 1.
FIG. 3 is a rear elevation view of the motorcycle fork shown in FIG. 1; and,
FIG. 4 is a right elevation view of the motorcycle fork shown in FIG. 1.
The broken lines immediately adjacent the shaded areas represent the boundaries of the claimed design and form no part thereof, while the other broken lines show environment and form no part of the claimed design.