The ornamental design for a bicycle fork, as shown and described.
FIG. 1 is a perspective view of a bicycle frame including the claimed bicycle fork;
FIG. 2 is a top plan view of the bicycle fork;
FIG. 3 is a side view of the bicycle fork;
FIG. 4 is a front view of the bicycle fork;
FIG. 5 is a rear view of the bicycle fork;
FIG. 6 is a bottom view of the bicycle fork; and,
FIG. 7 is an enlargement view of a front end portion of the bicycle fork.
The portions of the bicycle fork shown in broken lines form no part of the claimed design. The dash-dot lines are provided to define the bounds of the claim but do not form part of the claimed design.