TOPIC:

My 77 KZ650C developed a short that keeps blowing the 20A fuse. Using the schematic, I tracked it down to a device the schematic refers to as the regulator, shown here.


However, when I looked up a regulator on Z1 Eterprises, this is what I found.


So, what is my problem part?

Next, if this the regulator, can I disconnect the output (the terminal shorted to ground) and take a short ride? I know that best case it will only run until the battery runs down, but I want to make sure no other electrical faults exist. I also want to make sure nothing will get damaged.

Post edited by: steell, at: 2007/05/20 00:11

How do I get the images to show up larger?

The '77 KZ650's had seperate reg and rec unit's (shown in your 1st pic).
The '78~ KZ650 models had a combined (shown in 2nd pic you posted) reg/rec unit.

IIRC, they are powered like so:
'77 = 3-phase charging system
'78~ = 2-phase charging system

loudhvx or one of the other electrical gurus would be better able to explain the differences to you than I can, and be able to tell you if the newer ('78~) reg/rec unit can be adapted to fit your bike or not.

I think it's 77-single phase, and 78-three phase, but I could be mistaken.

If it has three yellow wires coming from the stator, then it's three phase.

Anyway you cut it, the 77 and 78 are different

To change the size of the pics, just edit your post and change the "size=150" default, to "size=350", or anything 550 or less.

I edited your post and changed the pic size to 350.

On your bike (this does not apply to later models with the permanent magnet alternator), if you disconnect the wires going to the regulator, then the alternator will be disabled and you can run on battery power.

Post edited by: steell, at: 2007/05/20 00:20

The 77 650s use a three phase excited field alternator and a separate regulator and rectifier. The part in the first pic is the regulator alright, it´s an electromechanical device that can be opened (see below), cleaned and adjusted - the procedure for testing, cleaning and adjusting the regulator points gaps is in the 650 manual (pg. 154-155 if you have a Clymer).

It´s a bit difficult to see in your pic, but it looks like you have a disconnected wire on the regulator? Looking at the regulator the way it sits on the bike the lowest pin should have a brown wire coming from the flasher relay, the middle pin should have a green wire going to the alternator (to the field coil actually) and the top pin should have a black/yellow wire that connects to ground.

Before spending any money make sure all wires are connected correctly and go through the tests to make sure the regulator really is the culprit - also check for pinched wires, the short may very well be elsewhere.

If it turns out it is indeed the regulator you can get a new one from Oregon Motorcycle Parts , he builds his own. Here´s a direct link to the regulator page: Click.






Post edited by: OnkelB, at: 2007/05/20 07:27

OnkelB wrote:

The 77 650s use a three phase excited field alternator and a separate regulator and rectifier. The part in the first pic is the regulator alright, it´s an electromechanical device that can be opened (see below), cleaned and adjusted - the procedure for testing, cleaning and adjusting the regulator points gaps is in the 650 manual (pg. 154-155 if you have a Clymer).

Wow! Thanks for the info. I looked through my Clymer manual and I didn't see that.

OnkelB wrote:
It´s a bit difficult to see in your pic, but it looks like you have a disconnected wire on the regulator? Looking at the regulator the way it sits on the bike the lowest pin should have a brown wire coming from the flasher relay, the middle pin should have a green wire going to the alternator (to the field coil actually) and the top pin should have a black/yellow wire that connects to ground. [/quote]

The wire was connected when the ground fault condition exists. I removed it during troubleshooting. I just didn't connect it back for the photo.

OnkelB wrote:Before spending any money make sure all wires are connected correctly and go through the tests to make sure the regulator really is the culprit - also check for pinched wires, the short may very well be elsewhere.[/quote]

Thanks, everyone for the info. I'll do some testing first to see if I can fix it myself.

BTW, will it hurt anything to take a short ride with this brown wire (regulator output I think) disconnected?

bemoore wrote:

BTW, will it hurt anything to take a short ride with this brown wire (regulator output I think) disconnected?

Hmm, I can´t say for sure, I´m not really electrically gifted, so I hope Lou (loudhvx, our residential electrics guru) will get here shortly, he´ll know.

I think what you would want to do is remove both the brown and green wire from the regulator and connect them with a jumper wire, that´s what you do when testing the charging system (pg. 149 in the Clymer). Note that if you leave the brown and green connected to each other you´ll drain he battery.

It´s your bike and your call, but personally I wouldn´t even run the engine until I found out why the main fuse blows - melting harness smells awful.

OnkelB wrote:

It´s your bike and your call, but personally I wouldn´t even run the engine until I found out why the main fuse blows - melting harness smells awful.

Agree on the melting harness, but I think I've found the reason for the blowing fuses. I just wanted to see if any other electrical faults are present. I didn't find any with my DMM.

The brown wire powers the regulator. The regulator powers the field-coil via the green wire. If the brown wire is left unconnected, the alternator will make no power, but won't use any power either, so the bike will run ok until the battery runs out of power. (As Steell mentioned earlier).

I would run it that way until you find the source of blowing fuses.

Connecting the green wire to the brown will put full power to the field-coil and, thus, the alternator will put out full power, unregulated. Don't rev the bike like this without a voltmeter on the battery to make sure the voltage stays below 15v.

Also, leaving the brown connected to green while the key is "on" will eventually drain the battery (like OnkelB said).

I did some more testing last night. Both the regulator and the rectifier tested good. I suspect a pinched wire now. On the regulator I cleaned the contacts and adjusted it. After I put everything back together, the short is gone. I ran out of time to track down anything else.