More voltage regulator weirdness!

Bike is a 1982 KZ750H3 4 cylinder. Recently I have posted with regulator/rectifier problems, complaining that my second unit has failed. I have done all the possible things like looking for shorts or open wires, bad connections, checking the phase outputs, etc with nothing
bad found. So I decided to pull the regulator and start looking for another one.

First I pulled the regulator output wire (red and white one) that feeds the battery...then I stopped. I decided to read that wire to ground for voltage with the engine idling just for kicks. I expected to see no voltage (as I assumed the regulator was dead). Instead, I got 35 volts!! Huh?? If it's putting out that much voltage at idle, why am I only seeing battery voltage at the battery when running with it hooked up??


I'm sure there is a simple explaination for this, so can someone fill me in? Thanks!

polkat wrote:

Bike is a 1982 KZ750H3 4 cylinder. Recently I have posted with regulator/rectifier problems, complaining that my second unit has failed. I have done all the possible things like looking for shorts or open wires, bad connections, checking the phase outputs, etc with nothing
bad found. So I decided to pull the regulator and start looking for another one.

First I pulled the regulator output wire (red and white one) that feeds the battery...then I stopped. I decided to read that wire to ground for voltage with the engine idling just for kicks. I expected to see no voltage (as I assumed the regulator was dead). Instead, I got 35 volts!! Huh?? If it's putting out that much voltage at idle, why am I only seeing battery voltage at the battery when running with it hooked up??


I'm sure there is a simple explaination for this, so can someone fill me in? Thanks!

When you pulled the red/white wire, there is no current flowing, that means there will be no voltage drop. If you put it under load, then the voltage will drop.

Could also be an intermittent problem on the reg/rec.