go from center of gear and draw line going across the top and bottom of the mag(front) hole, to the edge. These are your 0*. The bottom mark, go 147* counterclockwise, and the top hole, go 65* clockwise. Mark those 2-points and align the rv with them. The valve should be covering the back hole, while the front piston is at TDC, while makingthese markings...:cheers: