Retard mark (smaller drilled dot) should not move into timing hole at idle speed.

Figure 5-19. Checking Timing with Strobe Light


If a strobe timing light is not available, approximate timing can be obtained in an emergency, by using the following procedure:

Remove screw plug from timing inspection hole (11) in left side of crankcase. Then remove front push rod cover so that opening and closing of valve can be observed.

Turn engine in direction in which it runs until front piston is on compression stroke (just after front intake valve closes), and continue turning engine very slowly (less than 1/2 revolution) until piston top center timing mark (13) on flywheel is aligned in the inspection hole (11) as shown.

The narrow lobe cam is now at the approximate point at which contacts (10) open and front cylinder ignition spark occurs. When the wide cam lobe opens the points, rear cylinder ignition spark occurs. Connect a circuit tester such as a light bulb across the contact points to determine the exact point of contact opening. Loosen circuit breaker plate screws (6) just enough to shift circuit breaker plate (8) using a screwdriver in notch (9), so contacts will open exactly when piston top center timing mark (13) is aligned in inspection hole (11) as shown in Figure 5-18.

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