Ignition System

Circuit diagram

Description

This model is equipped with a battery operated, fully transistorized breakerless ignition system. By using magnetic pick-up coils the need for contact breaker points is eliminated. This adds to the dependability of the system by eliminating frequent cleaning and adjustment of points and ignition timing. This T. C. I. (Transistor Control Ignition) unit in corporates an automatic advance circuit controlled by signals generated by the pick-up coil. This adds to the dependability of the system by eliminatng the mechanical advancer. This T. C. I. system consists of two main units; a pick-up unit and ignitor unit.

Operation

The T. C. I. functions on the same principle as a conventional D. C. ignition system with the exception of using magnetic pick-up coils and a transistor control box (T. C. I.) in place of contact breaker points.

1. Pick-up unit

1 Pick-up coils

This unit consists of two pick-up coils and a magneto mounted on the crank-case (L. H.). When the reluctor (timing plate) projection passes the pick-up coil, the two signals are generated at the pick-up coil and transmited to the ignitor unit as a signal. The full ignition advance is determined by the width of the reluctor (timing plate) projection.

2. Ignitor unit

1 Ignitor unit (T.C.I, unit)

This unit has such functions of wave form, duty control, switching, electrical ignition advance, and etc. The ignition timing is advanced electrically using two signals from the pick-up coil. The duty control circuit is provided to control the on time period of the primary ignition current to reduce the electrical consumption. This unit also incorporates a protective circuit for the ignition coil. If the ignition switch is turned on and the crankshaft is not turned, the protective circuit stops current flow to the primary coil within a few seconds. When the crankshaft is turned over, the current is turned on again by the signals generated by the pick-up coils.

CAUTION: Do not run the engine without any spark plug cap(s) in place. Due to the high secondary voltage, it is possible to damage the internal insulation of the secondary coil.

Inspection

The entire ignition system can be checked for misfire and weak spark using the Electro Tester. If the ignition system will fire across a sufficient gap, the entire ignition system can be considered good. If not, proceed with individual component tests until the problem is found. 1. Warm up engine thoroughly so that all electrical components are at operating temperature.

2. Stop the engine and connect the tester as shown.

3. Start the engine and increase the spark gap until misfire occurs. (Test at various r/min between idle and red line.)

Minimum spark gap: 6 mm (0.24 in)

CAUTION: Do not run engine in neutral above 6,000 r/ min for more than 1 or 2 seconds.

Troubleshooting Chart

Check entire ignition connections.	Poor connection ►	Correct.
▼ OK
Check battery voltage and specific gravity.	Low voltage/specific gravity ►	Recharge battery.
▼ OK
Check fuse and fuse connections.	Weak connection or open circuit ►	Correct connection or replace fuse.
▼ OK
Check ignition coil resistance (primary and secondary). Primary: 2.7Ω ± 10%@20°C (68°F) Secondary: 13.2KΩ ± 20%@20°C (68° F)	If other than specified ►	Replace ignition coil.
▼ OK	If other than specified ►	Replace pickup coil assembly.
Check pickup coil resistance. Pickup coil: 120Ω ± 10% at 20°C (68°F)
▼ OK
Check operation of sidestand switch (if fitted) and relay.	Faulty ►	Check sidestand relay sidestand switch, diode and neutral switch.
▼ OK
TCI unit is faulty, replace unit.

 

Ignition coil

1. Coil spark gap test.

a.    Remove the fuel tank and disconnect the ignition coil from wire harness and spark plugs.

b.    Connect the Electro Tester as shown.

CAUTION: When testing twin secondary lead coils, one lead must always be grounded and the other lead may not exceed the maximum spark gap because the insulation on the secondary windings may be destroyed by the overly high voltages that can be generated.

c.     Connect fully charged battery to tester.

d.    Turn on spark gap switch and the increase gap to maximum unless misfire occurs first.

Minimum spark gap: 6 mm (0.24 in)

2. Direct current resistance test

Use a pocket tester or equivalent ohm-meter to determine resistance and continuity of primary and secondary coil windings.

Primary coil resistance:

2.7 Ω ± 10% at 20°C (68°F) Secondary coil resistance:

13.2 KΩ ± 20 % at 20°C (68°F)

Pick-up coil

1. Inspection

a.     Remover the seat.

b.    Disconnect the pick-up coil leads from the ignitor unit.

c. Check the resistance of the pick-up coil windings with the pocket tester. If the resistance is not within specification, replace the pick-up coil assembly.

Pick-up coil resistance:

1 20 Ω ± 10 % at 20°C (68°F)

1 Black 2 Orange 3 Brown

Spark plug

The life of a spark plug and its discoloring vary according to the habits of the rider. At each periodic inspection, replace burned or fouled plugs with new ones of the specified type. It is actually economical to install new plugs often since it will tend to keep the engine in good condition and prevent excessive fuel consumption.

1.      Inspection

a.     Inspect and clean at the specified intervals and replace as required.

b.    Clean the electrodes of carbon and adjust the electrode gap to the specification.

2.      Installation

Be sure to use the proper reach, type and electrode gap plug(s) as a replacement to avoid overheating, fouling or piston damage.

Type: BPR8ES (NGK) Electrode gap:

0.7 — 0.8 mm (0.028 — 0.031 in) Tightening torque:

20 Nm (2.0 mkg, 14ft-b)