Headlight Diode block

Hello everyone This is my first post here hope to make great friends with everyone. I just recently built an XJ650 from the frame up and am having 1 little problem. The diode block in the front of the bike behind the headlight seems to want to over heat when I start the bike and only when Its running do I get this problem. Its getting so hot It melting the wax covering around It and starts smoking something fierce. Im not sure what this thing does or what Its for. I have tried looking On the net for a solution and ended up here. I unplugged this Diode and It has no affect on any of the bikes functions. Should I leave It off? of maybe fix the problem? any help would be greatly appreciated. Thanks! :lol:

 

There used to be a site that had a PDF of the Haynes manual for these bikes, but I can not find it any more.

If you have access to a manual there is a schematic for the diode block. It is quite simple. I built a replacement with about 50 cents in parts (hmm, a few diodes, a resistor I think, and some crimp connectors). Works well. I encased the diodes in epoxy.

Let me know if I can be of any help

 

well I have switched this unit out with 2 other one thinking maybe I had a bad diode and they do the same thing. According to the wiring diagram Its the white wire on the diode doing this, which seems to be tied to the rectifier as well as the AC generator. Im lost Im not sure what to do or whats causing this.

 

You have a short somewhere, or if you went with the "minimalist-tribal-primitive" approach to wiring the bike, something is too primitive and is going somewhere it shouldn't.........

 

Re: Headlight Diode block overheating

Weird, I'm having the same exact issue -- only when the bike is running. I haven't really investigated it yet just wanted to see if there was something about this in the forum. If anyone has found the solution, let me know.

Thanks a bunch!

 

I'd like to know if anyone has found a solution to this. I too have had this issue.

 

Unfortunate that the original poster (long time gone) never shared if he solved this. But like chacal says above...

Or, another scenario with a stock bike is to inadvertently install a starter cutoff relay in the headlight relay location. The internal diode in the starter cutoff relay provides a path to ground for the white wire so when the bike is started the one leg of the AC Generator that is fed to the headlight relay through the diode block diode is basically shorted to ground. Note this would only occur in neutral, and could also inflict damage to both the starter cutoff relay internal diode and the neutral switch.

Refer to this thread for the proper location of the relays - note that some of the manuals have it wrong for some of the XJ's.

https://www.xjbikes.com/forums/threads/the-ultimate-relay-switch-sensor-and-diodes-guide.27543/

 

thanks Rooster53