Required tools for setting ignition timing: a tachometer, good quality timing light, dial indicator with spark plug hole adapter, permanent marker with a sharp point.

Hock up timing light, place magneto in full advance position, run engine between 4,000 and 5,000 rpms, observe location of timing mark on rope plate in relationship to the lip of the magneto just outside of the rope plate, the timing mark on the rope plate should be on the forward port side of the motor while running, mark the location of the timing mark on the lip of the magneto, the mark you made should line up close to the (M) in the word Yamato cast in the top of the magneto.

Shut off motor, remove number 1 spark plug, install dial indicator, rotate engine till you’ve located TDC, zero the dial indicator, rotate the rope plate backwards (counter clockwise) till you reached desired timing (OEM spec is .200” to .250” BTDC) at this point do not rotate rope plate, loosen up mag lock nuts or adjuster stop bolt, rotate magneto to line up the mark you made with the timing mark on the rope plate. Tighten mag lock nuts or adjust mag stop to magneto. Remove test equipment, reinstall spark plug, You now ready to go racing ;-)))

For future timing adjustments you will only need to perform the last paragraph.