Home made tach calibrator
I replied to this before, so this may be a repeat. Stick some white tape, paint dots or paper on the crankcase pulley. In reduced light, shine a regular a/c powered flourescent bulb on the pulley. At 1,800 RPM you should be able to see 4 separate stable white marks hovering at 90 degrees from one another. At 3,600 RPM there should be 2 markes at 180 degrees.
