Originally Posted by Bikeguy Joe
Those, and the early Honda 90's had two sprockets, one fit over the other. When you wanted to go to the other sprocket, you would remove the masterlink, remove (or add) the section of chain, pull (or push depending on which one you wanted to use) the other sprocket out of the way (it was on pins if I remember right) and re-install the master link.
That makes sense.
I was thinking the same thing that mechanickid pointed out, and wondered how it was done.