The Honda NTV Revere mounted different rectifiers across the years (e.g. models NTV650J, NTV650K and NTV650L). They have the OEM part numbers 31600MS9000, 31600MS9003 and 31600MS9010. They should all be interchangeable because they are mounted with the same stator (part 31120MS9004) and the same battery.

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 readings were taken on the kΩ scale, some on the kΩ scale, and some on the diode mode.

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 generator 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.

Using the DT-182 Mini multimeter on the 200 Ω scale, the reading with the terminals shorted is 0.4 Ω, measuring each coil the reading is 0.8 Ω instead.

The male connectors are attached to the regulator/rectifier.

*) NOTICE: Only older Honda part 31600MS9000 measure the resistance value, newer part 31600MS9003 measure ∞.

Values measured on the diode scale may vary by +/- 2%, values measured on the MΩ scale may vary by +/- 5%.

The following picture represents the schematic of a generic regulator/rectifier for a three-phase alternator (credits to www.homemade-circuits.com), it is not the schematic of the Honda part, use it just 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.

You can measure the A.C. voltage generated by each of the three generator coils with a multimeter at the black 3P connector, measuring each of the three yellow wires two by two. Each coil should produce about 6 V (A.C.) at 3000 rpm.

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