Its right hand thread, I would call it a snug fit,best way to get it off if it doesn't pull off by hand try using a puller. Before installing the new pulley, clean crank with some emery paper and apply anti-size. If still a bit tight going on then tap with a rubber or nylon hammer. As for how tight it should be done up I'm not sure, I've always used a rattle gun to do mine up.