Rectifier Melting Harness - Very Hot - XJ700X

Well... Moving along with my project, I am getting more run time. Today while syncing the carbs, I notice some smoke coming from the left side cover. I pop it off and see that the wiring harness that goes to the rectifier is melting. Again it appears, since it looks like it has some old damage too.

I touch the rectifier, and it's pretty dang hot. So, any ideas on where I should look now on the X? What would cause the rectifier and wires to overheat?

Thanks for any thoughts...

 

Found it. It just didn't make sense that this appeared. Two of the wires had melted together creating a short. Separated those two, and all seems well.

 

Are those the white wires? Does your alternator still work now? I found mine fused at the connector, melting the harness, wires, both sides of the connector together.

 

I wold also check the output voltage and make sure it is not overcharging. I have some wires that have evidence of heat damage at that location also but its the symptom, not the problem.

Mike

 

High output can be a bad charging system, or high resistance in the wires. Check your connectors aren't corroded. More resistance, more heat, more melting.

 

Yes, it was the white wires that fused. Alternator appears to be working since it is not draining the battery during run time.

I haven't measured the output voltage, but I should. I'll put that on the list. Thanks for the reminder.

I think what happened was that the PO's just hardwired the red wire after an initial failure and left the remainder in the harness with corroded connections. Which continued to be a problem since the corrosion didn't get any better. What I did was clip out the harness and just put waterproof male/female connectors on each of the wires. Trick was that there were 3 white ones. So, I stripped them with a sharpie (1 stripe to 3) so I knew which one was which. What I have noticed is that now the rectifier does get warm as expected during run time, but it is far from the firecracker hot it was.

 

Now that I'm putting a '82 harness in my '81 Seca 750, I notice it doesn't plug into the rectifier,(the connectors are different) no problem, just steal one from the Turbo 650.
Now for the question on my burnt, fused wires at the Alternator-harness connection- - does it matter which of the 3 white wires re-connects to the 3 black ones? Will nothing bad happen if they are mixed-up??

 

No. In our case it doesn't matter. They just go through a set of diodes that rectifies the current.

Mike

 

^^+1^^ Plug away, you need not worry about order.