I have no idea how long it had been sitting there. The guy I bought it from said his son bought it to fix up and use, so I assume it was already motorized though not being used. It's going to take a little (lot?) of work to get it in running order, but I'm happy to do the work on a classic bike.
Finding a bike like this by chance seems pretty slim to me, but finding one that was already
motorized seems astronomical.
BTW, I'm planning a boardtrack style build.