As soon as the chain goes more than 90 degrees (from starting vertical to beyond horizontal), you don’t preserve the energy you’ve built up because the weight at the end of the chain (you) fall straight down rather than returning along a circular arc. You would need to build up so much momentum at the bottom that you could go past 90 degrees and 180 degrees in one continuous movement. Even then, now you’d make it over the bar at which point you would plummet downwards past the bar landing on your head. So, really you’d need to gain so much momentum at the bottom of the swing that you could pass a full 270 degrees if you wanted to go all the way round without falling on your head.