Unplug the alternator output wires from the main harness......
With a multi-meter (or other means) FIRST verify that none of the three output wires (Pink, Yellow, and White) are contiguous to the engine case......
They SHOULD show continuity to each other (although with varying amounts of resistance)......If it passes these, you can start the actual test.....
Start the engine and read AC Voltages across the three possible pairings (Pink/Yellow, Pink/White, and Yellow/White)....
IF the actual wire colors have "vanished/faded/or bled onto each other" is inconsequential......Testing will sort them out for you.....
AT IDLE, the highest Voltage output will be from Pink to Yellow, usually in the 17 to 20 AC Volt range......
The second highest reading will be Pink to White (usually 14 to 18 VAC)which allows you to determine which wire was common
(to the previous two tests) and label it as the Pink wire....
The Lowest reading (dramatically lower) will be from Yellow to White, and is often as low as 3 to 6 VAC.......
IF all the pairs match those ranges at idle AND increase output with increased revs, the alternator is likely fine......
Also NOTE that Honda made a few changes to their wire color code versus wire purpose about the 1968/69 models, and this is stated below as it relates to the alternator wiring.
"Early" alternator wiring colors were Yellow, Brown, and Pink.
The Yellow comes out of the alternator and goes to one of the rectifiers AC terminals AND to the SE (selenium) terminal of the ignition switch.
The Brown wire goes to the other rectifier AC terminal.
The Pink wire goes to the DY (dynamo) terminal of the ignition switch...
Later alternator wiring colors were Yellow, Pink, and White.
Now, Yellow still goes from the alternator to one rectifier AC, but goes to the SE terminal of the headlight switch, instead of the ignition switch.
The Pink wire goes to the other rectifier AC terminal.
The White wire becomes a "White with Yellow tag" wire as it progresses to the headlight switch DY terminal in order to differentiate it from the headlight "low beam"
White wire from that same switch.
With a multi-meter (or other means) FIRST verify that none of the three output wires (Pink, Yellow, and White) are contiguous to the engine case......
They SHOULD show continuity to each other (although with varying amounts of resistance)......If it passes these, you can start the actual test.....
Start the engine and read AC Voltages across the three possible pairings (Pink/Yellow, Pink/White, and Yellow/White)....
IF the actual wire colors have "vanished/faded/or bled onto each other" is inconsequential......Testing will sort them out for you.....
AT IDLE, the highest Voltage output will be from Pink to Yellow, usually in the 17 to 20 AC Volt range......
The second highest reading will be Pink to White (usually 14 to 18 VAC)which allows you to determine which wire was common
(to the previous two tests) and label it as the Pink wire....
The Lowest reading (dramatically lower) will be from Yellow to White, and is often as low as 3 to 6 VAC.......
IF all the pairs match those ranges at idle AND increase output with increased revs, the alternator is likely fine......
Also NOTE that Honda made a few changes to their wire color code versus wire purpose about the 1968/69 models, and this is stated below as it relates to the alternator wiring.
"Early" alternator wiring colors were Yellow, Brown, and Pink.
The Yellow comes out of the alternator and goes to one of the rectifiers AC terminals AND to the SE (selenium) terminal of the ignition switch.
The Brown wire goes to the other rectifier AC terminal.
The Pink wire goes to the DY (dynamo) terminal of the ignition switch...
Later alternator wiring colors were Yellow, Pink, and White.
Now, Yellow still goes from the alternator to one rectifier AC, but goes to the SE terminal of the headlight switch, instead of the ignition switch.
The Pink wire goes to the other rectifier AC terminal.
The White wire becomes a "White with Yellow tag" wire as it progresses to the headlight switch DY terminal in order to differentiate it from the headlight "low beam"
White wire from that same switch.
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