Blowing fuses on my 1978 xs650e...need guidance!

[jradvantage]

So, I've been working on this bike off and on for about a year. It ran (barely) and all the electrical worked; horn, blinkers, the whole works. Also, appeared to be stock, with the exception of the regulator/rectifier combo. I took off the air box and replaced with uni-filters and removed everything attached to the battery box and had it powder coated. Installed all the electrical stuff back onto the battery box and worked my way forward. Unhooked the rats nest inside the headlight bucket and powder coated the bucket and replaced the needed parts. Marked the wiring as good as I could before I took it apart. Wired everything back up (after I cleaned and dielectric greased the terminals). I installed a brand new, fully charged battery and with great anticipation, slowly turned the key to the "on" position...Nothing!

So, the first thing I checked was the fuse. It was blown. Put another fuse in, blown. It blew before I even had it all the way in. I unhooked the various electrical connections to see if disconnecting one would solve the blown fuse problem. Disconnecting the coupling (6 wires) that comes from the motor and connects to wiring harness appears to be the culprit. I've looked at the wiring schematic for my bike and am having a tough time figuring out what I should check next. Was hoping someone on the Board could give me some pointers on what to do next.

Attached is a photo and some descriptions of the wiring. Any help/direction is much appreciated.

John

 

[oldcoal]

If you have an ohm meter check for which wire that should not be grounding is grounded. If you do not have a meter and have a lot of fuses have all the wires unhooked install a fuse and hook the wires up one at a time till you blow that fuse. The last wire you hook up that blows the fuse it where your problem is

 

[jradvantage]

Thanks old coal. That makes sense.

John

 

[weekendrider]

There is a small gauge yellow and a brown the comes from the harness at the point where the rectifier plug is that go the rear brake switch.
The spliced in piece going to the blue on the safety switch what was it's original color?

 

[jradvantage]

Weekendrider,

It appears to be Blue.

John

 

[gggGary]

Hmm that 6 wire connector has the three whites (yellow) that go to the alternator and the two that go to the alternator brushes. there are early (to 79) and late (80 on) alternator charging setups. The early set ups have one brush grounded, the other is fed +12 from the regulator. But the late set setup feeds +12 to one brush and the other brush is grounded through the solid state regulator. My guess will be switched wires to the brushes, on an early system would connect 12 volts to ground. Or there may some mis-match of early/late components.

 

[weekendrider]

Do you have the rear brake light switch wired in?
If not, I wonder where the brown wire is for that?

 

[jradvantage]

Weekendrider,

Yes, the rear brake light switch is wired up.
The brown wire is there and hooked up (just can't see it in the photo).

 

[jradvantage]

Thanks gggGary,
I will check into that. I'm sure this will lead to more questions over the next day or so.

John

 

[weekendrider]

If you already have the brake switch wired . . .
I can't think of where that single yellow in your picture would go.

 

[retiredgentleman]

You may have the 6 pin connectors plugged into the wrong components. There are two
6 pin connectors. One goes to the rectifier and one goes to the alternator. I'm not sure if the harness is long enough to allow you to reverse those two or not.

The one that you say is yellow,yellow,yellow, red and black is actually white, white, white, red and black. You need to confirm that this harness connector is plugged into the rectifier (and not the alternator) that normally mounts under the battery.

A single yellow comes from the alternator centre point, stator windings, and should connect to another yellow at the Safety Relay.

If your bike now has a rectifier/regulator combo unit, rather than the stock individual rectifier and regulator, this does add some confusion to the wiring. Where is this combo unit mounted?

 

[jradvantage]

retiredgentleman,

It never dawned on me that those connectors could possibly be mixed up, but that was the problem! I suppose if I'd have left the original air box intact it would have been impossible to screw up. And that extra yellow wire? It's mate was on the other side. Go figure.

The light at the end of the tunnel just got bigger and brighter.

Thank you so much!

John