Regulators, rectifiers, and stators, oh my!
Oh, and batteries too. I've been taking out my 1979 Suzuki GS1000, while I am waiting for a part for my CBR. I charged up the four-year-old battery and went out to the Safeway in Golden. The battery was dead, and I asked everyone for jumper cables. They looked at me like I had three heads. Finally an old guy had them, but his arthritis was so bad he said I had to install them. Only took a second to start.
So I got a new battery from Auto Zone and charged it overnight. Using my digital voltmeter, it read 13.6 at idle and decreased to 12.8 at 5,000. A problem, since it should be 14-15.5. I disconnected the rectifier (It's so old it has separate rectifier and regulator) and checked continuity. It was fine.
I disconnected the regulator and found corrosion in the yellow wire. Cleaned it, connected it, and checked battery voltage: 15.9 at idle, increasing to 16.8 at 5,000. The voltage regulator is bad. Unbelievably, they are still available from Suzuki for $180. But all regulators are the about the same. I'm going to the junkyard and will get a $15 one from a Yamaha and only connect the regulator wires and leave the rectifier wires alone. I'm just glad it wasn't the stator, which is expensive and a pain to install.