I have no clue what it is for sure but the forks and gas tank look similar to a Honda. The frame with the 2 slats to mount the engine to reminds me of the Taiwan frames of the 70's. Engine doesn't look close to original because it has a gear reduction or something that was removed and looks much older than the rest of the bike. Could be a nice project but get rid of that seat pan before it dents the shit out of the tank.