Re: chain flop
If you're sure your tension and alignment is right on, you might be having problems with binding links. Try this: Remove the chain and lay it flat on a clean surface. Run your hand under it and lift looking for tight spots that do not swivel easily. Some of the kit supplied chains have been known to have tight or binding links which can cause rough running of the chain and de-rails. If you find links that do not swivel easily and you can't free them, you might want to consider replacing the chain with a good industrial #41 chain. Twisted chains are also not uncommon also. If your chain has a twist to it they are nearly impossible to make right. Not saying for certain this is your problem but its worth a try.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"