1978 KZ1000 LTD - Charging System Troubleshooting

So I've been fighting a lot of electrical demons the past 2 years. I've studied the KZ wiring diagrams like a monk studying illuminated manuscripts, but I cannot figure out this issue I'm having.

My battery keeps draining, so over time I troubleshot and replaced components. I've replaced the stator, regulator, rectifier, and most recently the battery itself. I thought the new battery did the trick when I first installed it, everything was running smooth. But the next time I tried to start the bike a few days later, the battery completely died after cranking over a few times.

I've tried putting my multimeter in series with the battery to see if there is a parasitic draw on the battery, but no current measurement was picked up. There's supposed to be some current when the bike is off, even if it's not parasitic right? I made sure my multimeter's fuses weren't blown and have extra fuses as well, so maybe something else is wrong. So I'm still not 100% sure if a parasitic draw exists or not.

I know for sure that the charging system is not charging the battery while the bike is running, because the voltage across the battery does not increase as I rev the bike up to 4-5k rpm. This stumps me, because I replaced most the charging components. The rotor seems magnetic enough, as it was able to hold up a big wrench. I checked the continuity between the alternator and the regulator/rectifier and saw no issue there. The bike's fuses are fine as well.

I'm sure the battery not charging while the bike is running predates me replacing all those components. The last time I actually rode the bike a few months ago the battery died and I had to push it home a few blocks. That's when I decided to work on the charging system, as well as rebuild the rear brake caliper to make sure it wasn't dragging on the disc and causing an extra load.

What other possibilities am I missing?

Don't for get that if it's not charging the systems on the bike will drain the battery quickly when running. How are you connecting your meter to check for a "drain" ? nothing on this bike should draw current once switched off

To test for a parasitic drain I disconnect the cables from the negative battery terminal, then attach one of the multimeter's leads to the negative battery terminal, and the other lead to the disconnected cables.

Have you moved the meter lead to the 10a position? Have you switched on a low current circuit with the meter in line to confirm the meter is working? (Forgive me if you know all this, I have no idea of your electrical skills)

This might help.
Steve

rumble.com/v7avpv4-testing-the-stator.html

 

we'll do some quick meter tests 

charge your battery

grab you meter set to AC V

locate the regulator /rectifier connector
do not disconnect the regulator rectifier connector for these tests
you will back probe the connector on the regulator rectifier side

should be 3 yellow wires, a brown wire, a red wire, and a black wire

you'll be focusing on the 3 yellow wires at the beginning.
i gave the yellow wires the letters A B C so you realize the wire combinations you will need to test.

remember this test will require your meter to be set to AC voltage

start your bike
measure the regulator rectifier side of the connector.
put your probes on A and B of the yellow wires
what is the AC voltage?

raise the rpm to 3000
what is the voltage?

move your probes to A and C
what is your voltage at idle?

raise the rpm to 3000
what is your voltage?

move your probes to B and C
what is your idle voltage?

raise rpm to 3000
what is your voltage??

set your meter to DC V

put your black probe on your negative battery post( metal part of the battery)
put the red probe on the positive battery post
what is your voltage??

move your black probe to the red wire at the regulator rectifier connector
what is your voltage??
you want to see a voltage as close to 0.0V DC as possible.
0.5V DC or higher means you have too much resistance on that red wire.

move your black probe to the brown wire at the regulator rectifier.
what is your voltage??
same thing here.. you want to see 0.0V DC

move your Red probe to the Negative battery post.

Put your Black probe on the black wire at the regulator rectifier
connector.
what is your voltage?
same thing here
as close to 0.0V DC

turn off bike


 

 

wrote:

To test for a parasitic drain I disconnect the cables from the negative battery terminal, then attach one of the multimeter's leads to the negative battery terminal, and the other lead to the disconnected cables.
 

Cables ?  As in more than one?  Perhaps just a typo?

Unless there’s an additional accessory connection that could be suspect...

Good Ridin'
slmjim & Z1BEBE