Honda NTV650 Revere - Regulator/Rectifier troubleshooting

The regulator/rectifier is a semiconductor device; you can use a multimeter to check its health status, but using different testers will result in different readings. Also using a different range (scale) with the same tester will result in different readings.

The Honda workshop manual for the NTV 650 Revere gives the reading values that should be obtained using the Kowa 07411-0020000 digital multimeter on the Rx100 scale. That multimeter is specifically manufactured for Honda and it has two special scales marked as Rx100 and Rx1 respectively, grouped under the label CDI Ω. These two scales are specifically calibrated to measure the devices of a capacitor discharge ignition.

Because I don't have the Kowa multimeter, I used a DT-182 mini multimeter and a DT9806 one instead. In this page I give the values measured by those multimeters, some reading were made with the kΩ scale, others were made using the diode setting:

Here are the pictures of the three multimeters:

Turn the ignition switch to off and disconnect the negative terminal from the battery; connect the multimeter in series to close the circuit. The multimeter must be on the ampere scale and it should read a leackage of max 0.1 A at 20 °C.

The regulator/rectifier connectors are behind the right side cover.

• Disconnect the 3P black connector (Yellow, Yellow, Yellow: The three-phase alternator coils)
• Disconnect the 4P white connector (Red/White, Red/White, Green, Green: to battery, positive and negative)

The female connectors are attached to the wire harness and to the generator.

The male connectors are attached to the regulator/rectifier.

The following picture represents the schematic of a generic regulator/rectifier for a three-phase alternator (credits to www.homemade-circuits.com), use it to understand how the rectifier diodes are tested:

With the ignition switched off, measuring the voltage at the terminals of the fully charged battery should read 13.0~13.2 V. A value below 12.3 V means an under charged battery.

Starting the engine and gradually increasing the speed to 3000 rpm, should read a voltage of 13.5~15.5 V at 20 °C. This is the standard charging voltage for an AGM battery.

Remove the main fuse and connect a multimeter in series to close the circuit. The multimeter must be on the ampere scale. Starting the engine and gradually increasing the speed to 3000 rpm, should read a current of 0.5 A at 20 °C. This is the standard charging current for an AGM battery.

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