The ignition system has two circuits, the primary circuit and the secondary circuit. The primary circuit consists of the battery, switch, primary coil, breaker points, condenser and associated wiring. The secondary circuit consists of the secondary coil, the spark plugs and associated wiring.

The circuit breaker is located on the gearcase cover on the right hand side of the motorcycle. It hastwofunctions. First, the breaker cam and contact points open and close the low voltage circuit between the battery and ignition coil causing the coil to produce high voltage discharge to the spark plugs. Second, the circuit breaker times discharge for proper engine firing.

The breaker points are operated by a cam with two lobes. The narrow lobe times the front cylinder and the wide lobe times the rear cylinder. A single ignition coil fires both spark plugs at the same time, but one spark occurs in the exhaust stroke of one cylinder and the other spark fires the combustible gases in the other cylinder tc produce the power stroke.

The advance mechanism is an extension on the camshaft and operates at half crankshaft speed. The spark timing cam is advanced automatically as engine speed increases and retarded as speed decreases through action of the flyweights in the circuit breaker base. This ensures correct spark timing to suit starting, low and high speed requirements.

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