Well a few things come to mind if the carrier is loose.Is the chain tensioner bolts backed out all the way.If they are then I would say the chain is too far stretched and time for a new one.Check the bolts,are they tight going on and are tough to turn.I had a problem like that and got a set of new bolts off ebay and it solved the problem.Also are you running an aftermarket swingarm,if so then on top of the carrier where the bolts go through on the inside is there a washer sized spacer(basically a washer) on each side.If not add one to each side.On the stock swingarms these spacers/washers are welded from the factory onto the swingarm.Check those few things and get back with the results.Good luck.