Honda permanent magnet charging system regulators take two forms, one in which the black battery voltage sensing wire is exposed, and later versions in which it isn't. This difference affects how each is bypassed during system testing. The earliest permanent magnet regulators having the exposed wire made it easy to dynamically test the regulator. You simply disconnected that wire. But when Honda reintroduced the redeveloped, more efficient permanent magnet alternator in the 1980s, they hid that black wire on the new bikes, making the dynamic regulator test look a little different. However, is still possible, even easy, but its not by disconnecting anything. The way the regulator is dynamically tested on these machines is by applying an external test load to the battery while the charge test is underway. What this does is ensure that the regulator will not activate, effectively eliminating it from the system during the test, in just the same way that yanking the black wire did in the 1960-1970s systems. This method has worked well for me.

Permanent magnet charging systems part 1
Permanent magnet charging systems part 2
Permanent magnet charging systems part 3