Hot (to touch) wire on the voltage regulator

Hi Everyone.

Last night I was working on my son's bike (1980 KZ440 LTD) I had it idling for a while and had the side cover off. I noticed that one of the two yellow wires was very hot to touch. It was not up against the heat sinks of the regulator or near any hot engine points so it would seem to be carrying an excessively high current.

Didn't have the manual handy so did not do any diagnosis of the charging system at that time, but wanted to see if anyone has encountered this. His bike starter is sluggish so I am suspecting the battery is on the way out. This makes me wonder if the battery is causing a high demand on the system translating into a high current draw on the alternator.

I'll try to get some tests done on the system but any input is always appreciated.

Thanks!
Andy

The yellow wires are the AC leads coming from the alternator. It's my understanding that these bikes all use a shunt regulator system so the total current coming from the alternator should be the same regardless of whether it goes to the battery and electrical system or gets shunted to ground by the SCRs. I suppose it's possible if one of the internal rectifiers is blown, it might be trying to run on only half of the AC cycle which would double the load on the other side and could make it cook(?)

Could just be the connection on that one yellow wire is dirty. That's most common reason for a wire running hot (near a connector).

Thanks for the quick replies. I'll try a couple of tests and post either the solution or more symptoms.