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1. Ignition timing is checked by observing the position of the timing marks on the rotor in relation to the timing plate on the field coil assembly.
2. The field coil assembly has one timing plate. The rotor has four timing marks. The first mark is identified by the letter "T". This means the piston is at "Top Dead Center". The next two marks, identified by the letter "F" stamped counterclockwise from them, is the point of proper ignition timing when fully retarded (engine stopped or idling). When setting ignition timing, set it so both cylinders fire between the marks (both ignition advance weights completely closed).
3. The fourth timing mark indicates 37° before TDC, the fully advanced ignition position.
Note: Each point gap should be checked first, and adjusted, if necessary. Then proceed with the timing adjustment.
4. Check the point checker for full scale deflection (infinity to Zero resistance), then hook the black lead to a good ground; the red lead to the gray point wire (right cylinder).
Caution: Ignition timing for each cylinder is set separately. However, it is absolutely necessary that the right cylinder points are timed BEFORE the left cylinder points. The right cylinder points are mounted directly to the ignition point base plate. The left cylinder points, however, mount on a separate plate that is in turn mounted to the large ignition base plate. If the left cylinder points are timed first, they will shift out of position when the base plate is pivoted to time the right cylinder points.
5. The letter "L" (for left cylinder) is stamped next to one set of points, the letter "R" (for right cylinder) is stamped next to the other set. This indicates which set of points fire which cylinder.
6. Rotate the crankshaft in the direction of running rotation (counterclockwise when viewed from the left side) until the right-hand set of points just start to open, as indicated by the point checker.
7. Check the rotor timing mark position. If the right-hand points are timed correctly, the timing plate will position between "F" stamped two timing marks on the rotor. If timing plate does not fall between the lines a corrective adjustment must be made to the points.
8. With the timing marks lined up correctly, loosen both base plate lock screws. Pivot the entire plate until the right cylinder points just start to open, (as indicated by the point checker).
9. Tighten down both lock screws and check the timing again to make sure the base plate has not moved.
10. To set left cylinder timing, repeat steps 4 thru 8, except to switch the point checker probe from the gray wire to the orange wire. The left cylinder points are held in place on the base plate by two different lock screws. Loosen both lock screws as shown in the accompanying figure and make the necessary adjustments.
11. With the point checker hooked up to the orange wire, rotate the crankshaft. The left-hand points must now open when the rotor mark lines up with the stator full advance mark. Switch the point checker lead to the right-hand cylinder and re-check.