Strange charging 76 KZ400 D

So I was not getting enough charging voltage at the battery. The rectifier, field coil and stator tested OK and I knew I needed to replace the regulator. I installed it on the bike last night and I've got an improvement, but I'm still not getting enough voltage at the battery. Now I get around 12.2v-12.5v at the battery at idle and around 13.8-14v at 4000rpm. This is an improvement because before I was getting the same 12.1v at idle and 4000rpm.

One interesting thing I noticed: when I disconnect the white lead from the rectifier and test just to that wire, I get about 20v from the charging system. Then I connect it to the 'Y" connection where one side goes to the + side of the solenoid and the battery and the other side goes to the fuse box. If i check the voltage then I get 12.2v at the fuse box and 12.2v at the solenoid/battery.

How am I losing voltage when I'm only going through 1 white wire? Is it a bad ground or something? All my fuses look OK.

One more thing that I noticed while messing around with it today. If I unplug the white wire coming from the rectifier, then the bike idles much smoother and speeds up a little bit. If I plug it back into the "Y" connection then it slows down and gets choppier.

I know this has to mean something, but I don't what!

I am no expert, and I am actually trying to fix my charging issues on my 76 kz400. Does the Y connector get hot? I would suggest just changing that connector it could be a short there and would be super simple to fix.

Let me know what you figure out, I may run into the same issue...

Have you been to this website? www.armbell.com/forum/viewforum.php?f=17...59c788f&mforum=kz400

freemonty wrote: So I was not getting enough charging voltage at the battery. The rectifier, field coil and stator tested OK and I knew I needed to replace the regulator. I installed it on the bike last night and I've got an improvement, but I'm still not getting enough voltage at the battery. Now I get around 12.2v-12.5v at the battery at idle and around 13.8-14v at 4000rpm. This is an improvement because before I was getting the same 12.1v at idle and 4000rpm.

One interesting thing I noticed: when I disconnect the white lead from the rectifier and test just to that wire, I get about 20v from the charging system. Then I connect it to the 'Y" connection where one side goes to the + side of the solenoid and the battery and the other side goes to the fuse box. If i check the voltage then I get 12.2v at the fuse box and 12.2v at the solenoid/battery.

How am I losing voltage when I'm only going through 1 white wire? Is it a bad ground or something? All my fuses look OK.

One more thing that I noticed while messing around with it today. If I unplug the white wire coming from the rectifier, then the bike idles much smoother and speeds up a little bit. If I plug it back into the "Y" connection then it slows down and gets choppier.

I know this has to mean something, but I don't what!

Un-plugging the White wire and getting 20 DCV sounds good. The reason it Idles up is because there is now no Load on the system.
Like esion said, could be just the connections. Does your white go into a connector? Then where, back to the battery or onto the post at the starter solenoid? Check all of the connections, any heat is resistance and will cause the voltage to be lost.

So I cleaned up some connections and put dilectric grease on there and I was getting the same readings.

I tested the battery with the bike off and got about 12.4v and then I took it out for a quick ride and tested the battery again without the bike running and got about 12.6v. So it looks like it's charging.

I retested all the outputs a few days later and after a few more quick rides and the voltage at the white output wire. It's not at the 14-15v specified in the manual, but the battery is charging so I'll just be watching it close.

Maybe the bike just needed to kick some of the dust off.....It had been sitting for at least 2 years.

Running great now though, thanks for the help.