Disassembling And Assembling


Remove ignition timer cover screws (1), cover (2) and ignition module (3). Remove timer plate screws (4) and washers (5). Remove trigger rotor bolt (6) and pull trigger

Figure 5-21. Ignition System Components — 19781/» to 1979

2. Ignition timer cover

3. Ignition module

4. Timer plate screw (2)

6. Trigger rotor bolt

7. Trigger rotor

8. Advance assembly

9. Sensor

10. Shield

11. Timer plate

12. Screw and washer (2)

13. Flyweight spring (2)

14. Flyweight (2)

15. Advance assembly base

16. Flyweight roll pin (2)

17. Cam stop roll pin

18. Register roll pin

19. Camshaft oil seal

20. Ignition coil

21. Spark plug cable (2)

22. Ignition coil terminal (FL) 22A. Ignition coil terminal (FX)

Figure 5-21. Ignition System Components — 19781/» to 1979

rotor (7) from advance assembly (8). Remove advance assembly from gearcase cover. To remove sensor (9) and shield (10) from timer plate (11), remove screws and washers (12).

To disassemble advance mechanism, unhook spring (13) from grooves in pivot pins and slip flyweights (14) with spring from pivot pins on advance base (15). Do not remove springs from flyweights unless they are to be replaced. Roll pins (16, 17, 18) are pressed in and can be replaced if necessary.


Inspect lip of seal (19) and replace it if worn or rough. Also replace the seal if there is any evidence of oil leakage into the timer compartment.

Check flyweight springs (13), and if bent or stretched, replace them. When installing, be sure that bent end of each spring is hooked through bottom of hole, and that upper looped end grips groove in pin tightly. See figure 5-22. Check for looseness of rotor (7) on shaft (15) and wear on sides of flyweight (14) ears which engage slots in rotpr.

Reassemble advance assembly and lubricate moving parts with Harley-Davidson "Anti-Sieze." Check operation by moving rotor in direction required to advance weights to their fully extended position. Then release the rotor and see if springs return to the fully retarded position. Correct causes of faulty action by cleaning and lubricating the shaft and flyweights with "Anti-Sieze" and replace weak springs. Lubrication of the advance assembly should be performed at 5000 mile intervals.


Assemble ignition timer parts in reverse order of disassembly with the following exceptions:

Advance assembly must seat squarely and firmly on end of camshaft.

Install trigger rotor (7) in correct position so that it engages both flyweights and flat side is next to roll pin (17). Tighten trigger rotor bolt to 20 to 24 in.-lbs.

Adjust sensor air gap and set retarded ignition timing as described in previous section. Check advanced ignition timing under running conditions as described in previous section.

CAUTION — When installing ignition module, make sure wires are not pinched.


Figure 5-22. Advance Unit Flyweight Spring Assembly


Figure 5-22. Advance Unit Flyweight Spring Assembly

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