Installing The Alternator

1. Install a new O-ring on the engine groove. Assemble the stator to crankcase securing with two lockplates and four screws. Install the plug retaining plate and screws.

After assembling stator to crankcase, use tool, Part No. 97225-55, to press rotor onto sprocket shaft so that it bottoms tightly against seal spacer. See Figure 5-16.

2. Attach the hoses to the inner primary housing and install the housing.

3. Attach the transmission to the inner primary using the four nuts and washers; or two nuts with washers and two bolts with washers. Do not tighten this hardware yet.

6. Re-install the starter motor housing and starter motor.

7. Reassemble the compensating sprocket, primary chain and clutch. Be sure to install same size spacers behind the compensating sprocket to ensure correct sprocket alignment. See "Removing and Installing Front Chain," Section 2.

8. Adjust the primary chain. See "Front Chain Adjustment," Section 2.

9. Re-install the inner primary cover and gasket.

10. Reconnect the solenoid wires and battery cables.

NOTE

After reassembly, primary housing must be airtight. Check using a Vacuum Gage, Part No. 96950-68. Remove one of the four chain inspection cover screws and install the vacuum gage in the hole. Pinch the vent hose shut between the inner primary and tee fitting. With the engine running at approximately 1500 rpm the gage should read 25-30 inches or more water vacuum. A significantly lower reading indicates an air leak into the chain housing.

11. Check the clutch adjustments. See "Clutch," Section 4.

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IGNITION SYSTEM — 1979 AND EARLIER

IGNITION TIMER

DESCRIPTION

The ignition system is a breakerless inductive discharge ignition system. It has two circuits, the primary circuit and the secondary circuit. The primary circuit consists of the battery, switch, primary coil winding, ignition timer and associated wiring. The secondary circuit consists of the secondary coil, the spark plugs and associated wiring. See schematic diagram, figure 5-17.

The ignition timer is located in the gearcase cover on the right hand side of the motorcycle. It has two functions. First, it opens and closes the low voltage circuit between the battery and ignition coil causing the coil to produce high voltage discharge to the spark plugs. Second, the ignition timer times discharge for proper engine firing.

The ignition timer includes a trigger rotor, sensor, electronic control module and advance mechanism. 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 to produce the power stroke.

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

OPERATION (Figure 5-17)

The trigger rotor (1) has two lobes, the small lobe fires the front cylinder and the large lobe fires the rear cylinder. The sensor (2) consists of a number of turns of fine wire wound on a core and is mounted on the timer plate so that the lobes on the trigger rotor pass in close proximity. The air gap must be adjusted to 0.004"-0.006."

The electronic control module (3) contains all of the solid state components used in the ignition system. Within the control module is an integrated circuit chip (4) which contains oscillator and demodulator circuits. The control module is fully enclosed in a silicone material to protect it from vibration, dust, water or oil. The unit is a non-repairable item. If it fails, it must be replaced.

When the ignition switch (5) and engine stop switch (12) are on, current flows from the battery (6) to the control module (3). An oscillator section in the integrated circuit chip (4) sets up a signal in the sensor (2). This creates a field around the sensor. When a trigger rotor (1) lobe leading edge enters the sensor's field, it reduces the strength of

Figure 5-17. Breakerless Inductive Discharge Ignition System — Schematic Diagram r-J^r

1. Trigger rotor

2. Sensor

3. Control module

4. Integrated circuit chip

5. Ignition switch

6. Battery

7. Transistor

8. Ignition coil

9. Spark plug

10. Main circuit breaker

11. Ignition circuit breaker

12. Engine stop switch

Figure 5-17. Breakerless Inductive Discharge Ignition System — Schematic Diagram

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the oscillating signal. I his weakened sensor signal is detected by what is called a demodulator circuit in the integrated circuit. The demodulator controls a transistor (7) which turns off the current in the ignition coil (8) primary circuit. This causes a high voltage to be induced in the secondary of the coil which in turn causes a spark at the spark plug gaps (9).

The time of spark plug firing is when the leading edge of each lobe aligns approximately with the center of the sensor as shown in Figure 5-18.

Figure 5-18. Trigger Rotor Position for Ignition Timing

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