Topic: Running into a wall troubleshooting overcharging issues, help!

[nholden98]

Greetings all,

Been awhile since I've posted here, haven't touched my CB in a year due to work and school. I was fighting a faulty charging system and finally replaced the reg/rec with some units from Oregon Motorcycle Parts, bike went from not charging to now overcharging. I'll try to include everything I have done so far:

- With the engine off, ignition/headlight/handlebar switch on, I am getting 12.3V at the battery and only 10.6 when checking at the black regulator wire and ground. This makes sense because my bike is overcharging by approx 1.7V at 3k RPM (measured between the red rectifier wire and ground).

- I hot-wired the bike to bypass the ignition switch (key), this did not impact any of the above values, so I presume this eliminates a faulty ignition. I am also getting perfect voltage going into the key, so no issues with power getting up to it.

- I unplugged the fuse box and used some jumper wires to bypass it at the plug for all 3 fuses, again no impact on the values above, assuming this means fuse box is OK.

- I checked all of the connections and everything looks clean. I've unwrapped some of the wiring harness but would really like to avoid going any further with that unless absolutely needed. The bike was rebuilt 5-6 so everything is in pretty good shape.

Here is where I am a little perplexed;

My understanding is that with the bike off, all switches/lighting turned on, the black wire going into the regulator should read the same as the battery voltage. I played around with the handlebar kill switch and headlight switch and got these values:

Battery voltage: 12.3V

Ignition on, killswitch/headlight off: 12.0V

Ignition/killswitch on, headlight off: 11.5V

Ignition/killswitch/headlight on: 10.6V

Shouldn't these all remain the same or very close to the battery voltage regardless of setting? I wont lie I am struggling at this point, any help is appreciated.

If anyone happens to be in the Richmond/Williamsburg, VA area, I'd happily pay them to get it right.

[nholden98]

Here’s a simpler question I hope I can at least get answered...should I see a voltage drop at all on the black wiring branch when the kill switch is turned on/off? This should tell me if I should expect a voltage draw from the ignition system with the engine off. I pulled apart the kill switch and cleaned its contacts already...

[scottly]

With the key on and the headlight and kill switch off, engine not running, there is a draw from the regulator/field coil, which is equal to or greater than the draw from the ignition with the kill switch on.
With any load on a battery, the voltage will slowly drop, and the greater the load, the greater the drop as measured directly across the battery terminals.
The best way to measure the voltage drop in the harness is to clip one meter lead to the battery positive terminal, usually the red one, and then use the other probe to measure the drop directly: this reduces the error from the battery voltage dropping under load.
Most problems like this are in connections, and don't require surgery on the harness.
BTW, this board is meant for M-units and related electronics, which is why such a slow response.

[nholden98]

Scotty, thanks for the response. That's my mistake, I clicked on the first thing that said electronics...oops.

[roach374]

BTW, this board is meant for M-units and related electronics, which is why such a slow response.

What's the right board for general electrical questions (unrelated to m-Unit)?