Need help with an 81 xs400 and not charging/fried a wire

[D-Run]

I have a 81 xs400. I have taken it for short rides without the battery charging and the bike runs absolutely great! I recently, as of tonight replaced the stator and stator field coil to fix the "not charging" problem. Prior to replacing them I tested both and they tested bad. I installed the "new" parts (their used), buttoned everything up added oil and fired the bike up. Within 15 second of the bike running I had a puff of smoke come from the wiring harness. I cut open the wiring harness and discovered that the white wire is fired!

Questions
What is the white wire for? It looks, from the wiring diagram that is supply power to lots of things
Why would/ what caused the white wire to fry after I installed the stator and stator field coil?
how screwed am I? I loath wiring.

Any help is greatly appreciated. Thank you!

 

[BBS360]

Where exactly did the damage happen?
Are your fuses intact?
Pretty sure there should only be three or four white wires in the harness. Maybe double-check the wiring diagram.
Should be three white wires from the stator to the rectifier, one of which splits off to the headlight relay and should have a series connected diode in a little transparent wrap.

 

[D-Run]

 

[Wolfe_11B]

Fried diode, yum

 

[D-Run]

what diode? what does a diode do? lol I know I should learn more about wiring and electrical work. but I hate.
Why would the diode fry after I installed the "new" stator and stator field coil?

 

[Wolfe_11B]

Short somewhere, wiring was wrong, bad rectifier... Could be a ton of things. But something is for sure amiss. Need some more background on the original problem. Did the charging system never work for you? Did you buy it like that? What 'tests' did you do to determine the stator and field coil were in need of replacement? Did you test them off the bike on on the bike with maybe some wires still connected? Did you check the regulator and rectifier as well? Did you mess with any kind of wiring? Did the previous owner?

 

[D-Run]

The bike had been sitting in a garage for about a year and a half or so and prior to that I'm not sure of it's history. when I got the bike the charging system never worked. the previous owner did not work on anything. I can double check that today, bought it from family. when I tested the battery it was at 12.7 volts and would slowly, very slowly drop. I did an ohm test on the regulator and rectifier as well as the stator and field coil. The rectifier and regulator test good per the requirements in the service manual. I tested them on the bike. when I did the ohm test I had the rectifier, regulator, stator and field coil all unplugged. I have not started looking at any other wiring. There hasn't been any suspicion or reason to dive into the wiring until. Everything works (worked) on the bike.

 

[Wolfe_11B]

Well it's not uncommon for those diodes to fry after being very old, but a bad diode doesn't go out in that extravagant fashion that you had. It was for sure getting pumped over it's limits, and seeing how it happened right after starting, I would look into something being wired wrong. That wire with the diode is basically an AC feed branched off of one of the stator winding's. It's there to turn on the 'auto-on' headlight relay, and serves no other purpose.

What I would do now is clean up the harness in the area where the diode went boom. Make sure no other insulation got burned through, wrap areas that did, etc. Ignore the burnt diode for now, just tape both loose ends of the white wire where it split. I would pull the headlight relay as well, just in case. Once the charging problem is solved you can focus on getting the headlight working again. After all that is done, then we can have a look see at the stator, field coil, regulator, and rectifier.

My hunch tells me you have a short in the stator, a short in the stator wiring, or a short in the rectifier. That would instantly kill that diode.

 

[D-Run]

does radioshack have replacement diodes that will work as a replacement? If so, what should I look for when getting one?