Norton Commando Workshop Manual

## Electrical

# J

4. | Ignition and Lights
| Again the Icey may not be removed. This position is used for night riding.
The lock with keys is captive in the switch body. If for any reason the lock need be replaced, it can be removed from the switch body to which it is held captive by a spring operatod plunger. A sharp pointed implement | such as a ground-down spoke wouid be ideal for depressing the plunger through the hole in the side of the switch body. Whilst depressing the plunger the | switch body should be shakon and the lock ejected.

### SECTION J11

### TESTING IGNITION SYSTEM

Testing Sequence for Ignition System
Engine; will not start - difficult to start - misfires.
(a) | Check battery.
(b) | Check main fuse (if fitted).
(c) | Check for spark at both spark plugs.
(d) | Ensure timing, contact breaker and spark plug gaps are satisfactory.
(e) | Check capacitor by substitution.
(f) | Check wiring for loose connections.
(g) | Test Zener Diode and ignition system.
(h) | Where fitted, check ballast resistor for short circuiting, when hot.

Ignition System Tests
(a) | Connect D.C. voltmeter Black lead to C.B. terminal of contact breaker and Red lead to earth.
(b) | Ensure contact points are open.
(c) | Switch on ignition. Voltmeter should indicate battery volts.
(d) | Ignition still on, close contact points. Voltmeter reading should fall to zero.
Note: Repeat the test for each coil with its appropriate contact set.

### CONCLUSION:

No reading for test (c) may indicate faulty ignition switch, open circuit primary winding, broken lead, short circuit to earth on C.P,. Iead, faulty capacitor or blown main fuse.
Low reading indicates high resistance in the primary circuit or across ignition switch contacts. A reading for test (d) indicates voltage drop across the contact points (dirty) or poor distributor earth.

### SECTION J12

### IGNITION COILS

The ignition coils whether of the 12 volt or 6 volt type consist of primary and secondary windings wound concentrically about a laminated soft iron core, the secondary windings being next to the core.
The primary winding usually consists of some 300 turns of enamel covered wire and the secondary some 17,000 - 26,000 turns of much finer wire - also enamel covered. Each layer is paper insulated from the next in both primary and secondary windings.
When the contact breaker opens, causing a sudden cut-off of current flow in the primary windings, H.T. current is induced in the secondary windings and a spark occurs at the spark plug.
Note: The coils are of the oil filled type and must be protected from mechanical damage which will cause leakage.

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