FIG. 1 is a perspective view, on a reduced scale, of a top, rear and left side of a motorcycle helmet attachment showing my new design; the broken lines are for illustrative purposes only and form no part of the claimed design;

FIG. 2 is a right side elevational view thereof; the left side being a mirror image;

FIG. 3 is a top plan view thereof; and,

FIG. 4 is a rear elevational view thereof.

The front and bottom of the motorcycle helmet attachment are unornamental and form no part of the claimed design.