I claim the ornamental design for a folding shifter or brake pedal for a motorcycle, as shown and described.
FIG. 1 is a top elevation view of the folding shifter or brake pedal for a motorcycle showing our novel design;
FIG. 2 is a bottom elevation view thereof;
FIG. 3 is a left side view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a front view thereof;
FIG. 6 is a rear view thereof;
FIG. 7 is a front and top perspective view thereof; and,
FIG. 8 is a rear and bottom perspective view thereof, wherein the dashed lines represent a shifter arm of a motorcycle and are not part of the claimed invention.