I have a '79 P200E that I've restored from the heap. Recently, I have had a problem with the battery charge being depleted after a few rides. I can tell when the voltage dips below 9V because the horn weakens, the signals stop working, etc. New battery, with a good initial charge, along with a replacement rectifier/regulator, has got me baffled as to the source of the problem.
Right now the battery has been depleted to about 1.5V (scooter off) and when you put a multimeter on the terminals with the scooter running, it doesn't get above 0.8V, throttle or not.
I suspect the regulator/rectifier may be the culprit, and it isn't replenishing the battery with the proper 12V charge during riding. But this is a new part replacement, and I am suspitious if it actually is the problem.
Is there a way to test the regulator with a multimeter directly on the regulator terminals, or is the only way to test it through the battery while it's on? Also, can anyone suggest any other tests to run to determine if this part is at fault or not.