Different reg/rec on bike

I have a 1977 kz 900 and i'm the third person to own it since its been "restored." the battery keeps on dieing after you ride it for a while. The bike had the reg. and rectifer replace with a '79 reg./rec. combo but the brown wire is just floating and not connected to anything. Is this keeping the bike from not charging, should i replace the reg/rec? HELP

The brown wire should be connected as it limits or controls the regulator/rectifiers output. Check the wiring diagram to where this wire should go as running it disconnected can damage several components.

www.electrosport.com has a troubleshooting diagram to follow about problems like this(I think).

brown wire is just floating and not connected to anything.

As can be reviewed in the attached image, this Brown conductor is your +12Vdc to the regulator! This should be terminated to the connector feed into the regulator for 1977 KZ900.

NOTE: There isn't a KZ900 in 1979 so must have come from a KZ1000...maybe?

KZ1000 used a different (OEM) part number for the regulator and an ignitor.

NOTE: My schematic is weird where to 5P connectors are depicted but shouldn't matter for troubleshooting or discussion.

It is terminated to connector 5p to the rectifier but it doesn't continue to the rectifier diodes.

OMR

To insure I was speaking out my ass again... I checked my KZ1000/1100 manual and the Brown wire is the +12Vdc feed into the regulator/rectifier combo unit.

OMR

Argggg... had to re-do to include image...

As Mfolks and OMR mentioned, the brown wire must get battery voltage while the bike is running. If not, you can burn up everything.

Since the original wiring didn't have it, you can tap into the wire that feeds the ignition or any other 12v source that is on when the ignition is on. However, if there are bad connections on the ignition switch etc, this will lower the voltage on the brown wire which will lead the regulator to send too much voltage to the battery. Make sure your connections and switches are good, and do a voltage check on the battery while revving around 3000 or 4000 RPM. It should go no higher than about 14.6v or so.

Since the brown wire is not connected and you are still having the battery die on you, maybe there is also another problem. Have you measured the battery voltage while it is running?

Any luck on your charging issue?

On another point,I thought there were a few 1977 900 engines installed on the early 77 production run and they were known as KZ900A5.

There was definitely a 77 KZ900A5. The brown wire should attach to ANY switched voltage source on the wiring harness but on a KZ900, there is a brown wire coming off the harness to attach to. The Auxiliary lighting unit is on the right side of the battery box and has a brown wire which you can splice into and connect to the brown wire on your reg/rec. You could also splice a wire to the RED wire running to the back of the bike which powers the running light in the rear light. This wire comes directly off the ignition switch. Your combo reg/rec won't work without the brown wire connected to a switched voltage source.

white can be hot at all times battery positive

but the brown wire is the SWITCHED HOT.

thru key switch or taillight positive feed. (easy to get to)


it might be time to peak potential test the stator, as to verify that you have over 75 A.C.V. on all 3 legs of your dynamo.