To make a wheel, first, you need to know the BTDC Timing Opening for your year/model. To find this, check the specs below for the proper BTDC opening. If you have a different engine than those listed, contact your dealer for opening specs.
You�ll need a piece of cardboard from something like a cereal box. Start by drawing a line horizontally about 6" long. Then mark a center point in the middle of the line. Next, use a protractor (centered on the center point) and measuring counterclockwise from zero (zero being the right end of the line), mark the BTDC TIMING OPENING degrees from the chart below.
Finally, using a compass mark inner and outer circles. The inner circle is 1.25" and the outer circle is 4.75". Cut out the inner and outer and you'll be left with a donut with zero point and BTDC Opening Degree point marked. [links]