I've had difficulty keeping the right slip-on tight on my RK Custom. Others with Touring models from H-D have indicated they have the same problem. The right side of the crossover exhaust on Touring models takes the bulk of the exhaust, therefore gets a lot more heat. I tightened one clamp to the point of breaking the bolt in it. I think I found a cheap cure:
I cut strips out of a soda can and put them between the slip-on and the header pipe, then tightened the clamp with a bit of authority. So far, so good. I heard folks suggest copper shim stock, but the 2 auto parts stores I checked had none. So I cheated by whacking up a soda can to make my own shims.