Special Tools - Grip: 57001-1591

Rotor Holder: 57001-1658

Torque - Alternator Rotor Bolt: 155 N·m (15.8 kgf·m, 114 ft·lb)

 

• Apply a thin coat of molybdenum disulfide grease to the shafts [A], and install them.

• Install the torque limiter [B] and starter idle gear [C].

• Install the alternator cover (see Alternator Cover Installa-

tion).

 

 

Alternator Inspection

There are three types of alternator failures: short, open (wire burned out), or loss in rotor magnetism. A short or open in one of the coil wires will result in either a low output, or no output at all. A loss in rotor magnetism, which may be caused by dropping or hitting the alternator, by leaving it near an electromagnetic field, or just by aging, will result in low output.

• To check the alternator output voltage, do the following procedures.

○Turn off the ignition switch.

○Disconnect the alternator lead connector [A].

○Connect the hand tester as shown in the table 1.

○Start the engine.

○Run it at the rpm given in the table 1.

○Note the voltage readings (total 3 measurements).

Table 1 Alternator Output Voltage

Tester Range	Connections	Reading at 4 000 rpm
Tester (+) to	Tester (–) to
250 V AC	One Black lead	Another Black lead	42 V or more

If the output voltage shows the value in the table, the al- ternator operates properly.

If the output voltage shows a much higher than the value in the table, the regulator/rectifier is damaged. A much lower reading than that given in the table indicates that the alternator is defective.

• Check the stator coil resistance as follows.

○Stop the engine.

○Connect the hand tester as shown in the table 2.

○Note the readings (total 3 measurement).

Table 2 Stator Coil Resistance

Tester Range	Connections	Reading
Tester (+) to	Tester (–) to
× 1 Ω	One Black lead	Another Black lead	0.18 ~ 0.27 Ω

 

If there is more resistance than shown in the table, or no hand tester reading (infinity) for any two leads, the stator has an open lead and must be replaced. Much less than this resistance means the stator is shorted, and must be replaced.

• Using the highest resistance range of the hand tester,

measure the resistance between each of the black leads

and chassis ground.

Any hand tester reading less than infinity (∞) indicates a short, necessitating stator replacement.

If the stator coils have normal resistance, but the voltage check showed the alternator to be defective; then the rotor magnets have probably weakened, and the rotor must be replaced.

Special Tool - Hand Tester: 57001-1394

Regulator/Rectifier Inspection

EX650A Models

• Remove: Bolts [A]

 

 

• Disconnect the connector [A].

• Remove the regulator/rectifier [B].

 

EX650B Models

• Remove the bolts [A].

• Disconnect the connector [B].

• Remove the regulator/rectifier [C].

 

 

Rectifier Circuit Check

• Check conductivity of the following pair of terminals.

Rectifier Circuit Inspection

Tester connection	W/BL-BK1,	W/BL-BK2,	W/BL-BK3
BK/Y-BK1,	BK/Y-BK2,	BK/Y-BK3

The resistance should be low in one direction and more than ten times as much in the other direction. If any two leads are low or high in both directions, the rectifier is defective and the regulator/rectifier must be replaced.

NOTE

○The actual meter reading varies with the meter used

and the individual rectifier, but, generally speaking the

lower reading should be from zero to one half the scale.

Regulator Circuit Check

CAUTION

The test light works as an indicator and also a cur- rent limiter to protect the regulator/rectifier from ex- cessive current. Do not use an ammeter instead of a test light.

To test the regulator out of circuit, use three 12 V batteries and a test light (12 V 3 ~ 6 W bulb in a socket with leads).

• Check to be sure the rectifier circuit is normal before con- tinuing.

• Do the 1st step regulator circuit test.

○Connect the test light and the 12 V battery to the regula-

tor/rectifier as shown.

○Check the BK1, BK2 and BK3 terminal respectively.

If the test light turns on, the regulator/rectifier is defective.

Replace it.

If the test light does not turn on, continue the test.

 

• Do the 2nd step regulator circuit test.

○Connect the test light and the 12 V battery in the same

manner as specified in the “Regulator Circuit Test-1st

Step”.

○Apply 12 V to the voltage BR terminal.

○Check the BK1, BK2 and BK3 terminal respectively.

If the test light turns on, the regulator/rectifier is defective.

Replace it.

If the test light does not turn on, continue the test.

 

 

• Do the 3rd step regulator circuit test.

○Connect the test light and the 12 V battery in the same

manner as specified in the “Regulator Circuit Test-1st

Step”.

○Momentarily apply 24 V to the voltage BR terminal by

adding a 12 V battery.

○Check the BK1, BK2 and BK3 terminals respectively.

CAUTION

Do not apply more than 24 V. If more than 24 V is ap- plied, the regulator/rectifier may be damaged. Do not apply 24 V more than a few seconds. If 24 V is applied for more than a few seconds, the regula- tor/rectifier may be damaged.

If the test light did not light when the 24 V was applied momentarily to the voltage monitoring terminal, the regu- lator/rectifier is defective. Replace it.

If the regulator/rectifier passes all of the tests described, it may still be defective. If the charging system still does not work properly after checking all of the components and the battery, test the regulator/rectifier by replacing it with a known good unit.

 

 

Charging Voltage Inspection

• Check the battery condition (see Charging Condition In- spection).

• Warm up the engine to obtain actual alternator operating

conditions.

• Remove the seat (see Seat Removal in the Frame chap- ter).

• Check that the ignition switch is turned off, and connect

the hand tester [A] to the battery terminals [B].