You didn't post a pic of the right side showing the drive line, so we have to guess. One thing, the return chain usually runs inside of the drive chain.

Dropping the chain may make a big improvement if you don't mind the chain rubbing during slow seed tight turns.

As for the bike, I concur that it is a TW or Performer model. If so, it can be a fine machine with some tweaking here and there. Bike has a lot f potential.