Loose Back Brake Calliper

A picture would help but a floating caliper is just that.

It depends exactly on what you mean by loose?

 

A floating caliper has some wiggle room but I wouldn't class It as loose.

 

Yup, normal on my 2010 Speed Triple and a 2016 I had
It is the caliper carrier that slides back and forth on the adjuster
There is some movement but just a little...2 to 3 mm
I think it is because it is a floating attachment over the main wheel pin thing and a bolt that slots into the carrier that allows the forward and back adjustment when you adjust the chain

If you think it is excessive, look at the bolt on the frame that sits in the carrier adjustment slot, maybe wear on the bolt, renew this or fit something that would be a tighter fit

 

Nothing to worry about SteveRS, it’s normal if it can move a bit.

 

It's actually more worrying if there is NO movement in the caliper or carrier. As this would indicate a likely rubbing brake pad , which would cause overheating and excessive wear on the brakes and disc.

Cheers capt