Battery Overcharging - Help!

The battery is overcharging on my '78 1000 A2. I tested the voltage per the manual and found too much voltage...17v+ at 4000 RPM. I bought a used voltage regulator and swapped it out. Exact same issue!

Is it likely that I have 2 bad regulators or could there be something else wrong? I checked the ground on the regulator and it's good. Any other suggestions?? Common issues?? Thanks

Reg is not dumping excess juice to ground. As much as it hurts, buy a new regulator.

RICK

77KZ650 w/ Dyna S, mildly chopped
81BMW r65
91 BMW k100rs 4v

Make sure your meter is working correctly. A low battery condition in some meters can cause false readings. Also the battery in the KZ1000 is OK? The regulator won't work if the battery is not there as a load.

iambinjieu wrote:

Reg is not dumping excess juice to ground. As much as it hurts, buy a new regulator.

RICK

77KZ650 w/ Dyna S, mildly chopped
81BMW r65
91 BMW k100rs 4v

That could the problem or you just have a poor path to ground. I like to run a jumper wire from the reg/rec ground straight to the Bat. Neg. post.

When this happened to me a few years back it was a wiring connecter problem and I found the answere here on KZR.

Te regulator/rectifier has a white wiring connector on each end. One end connects to a connector coming from the alternater. The other connector mates with a connector coming from the main wiring harness. This is where I had the problem.

Check the connector coming from the harness and jiggle the wires in the connector. In my case there was a brown wire which was seated ok but once I pulled it it fell out. Without this brown wire connecting properly the reg/rec was not getting the feedback it needed to keep the voltage down.

With 30 year old bikes these plastic wiring connectors get brittle and I have had more than one of them fall apart in my hands. My 2 cents worth is that your reg/recs could be just fine and to check the wiring really closely between the unit and the main harness. I know little about electrical so hopefully a guru will jump in.

Good luck.

79MKII wrote:

The battery is overcharging on my '78 1000 A2. I tested the voltage per the manual and found too much voltage...17v+ at 4000 RPM. I bought a used voltage regulator and swapped it out. Exact same issue!

Is it likely that I have 2 bad regulators or could there be something else wrong? I checked the ground on the regulator and it's good. Any other suggestions?? Common issues?? Thanks

Make sure the reg sense lead is connected to 12V or it will think the battery is low and charge wide open all day.

All very good suggestions / points. Here's the latest:

Good voltage to the regulator, good ground to the regulator, battery like new, meter is a good one and pretty new also. I have moved on to the Out of Circuit test according to the manual. The used one I bought has more than one issue and is junk. The original unit tests OK except for one reading.

When measuring between the black (ground) and brown (pwr) leads, there is a specific resistance reading that should be there. There are 2 readings depending on which lead you have connected to the positive from the meter. I think this is because of the thyristor or zener diode. Anyway, the reading should be 1,050 ohms with the meter (+) on the black and meter (-) on the brown. When the meter leads are reversed, it should read 300 ohms. Both of my regulators read 1,050 with the meter leads either way. According to the manual they are bad. Has anyone ever experienced this by any chance?? All other tests are OK on the original unit except this one. The manual does state though that the unit could be bad even if all readings are good.

I have a new aftermarket regulator that I might have to hook up but I was hoping to keep it factory. Oh well, I guess I have to hook up the new regulator and try it out.

Here's a link to the new regulator I have:

www.denniskirk.com/jsp/product_catalog/P...afCatId=&mmyId=10274

I installed the new regulator and all is well. I guess I did have 2 bad regulators after all. I guess that $20 was donated to Sierra_Recycled through eBay. Far too late to try for a refund now.

I was able to use the factory plug and wires by cutting them off of the bad regulator and soldering them to the new one. The new regulator also mounted in the stock location so it looks pretty much like factory. Problem solved. Thanks for the help!