reverse was a factory option
it uses a starter motor on one of the 2 clutch plates
yes they do, mine came pretty rounded and messed up, gonna need some grinding
I made a reverse on my scrambler out of an electric starter from a boat motor with a ring gear. It was only for temporary use to back off the trailer or out of the garage but it worked great. Used a 12V battery and a push button on the dash to fire a solinoid to run the starter.
Contact me for details,
Chad