I replaced ours yesterday, a Mikalor version, 45mm dia (DL650) it unscrews completely so you don't have to split the exhaust.
The old one had cracked apart near the bolt head, it required a bit of force to remove it because there were two 3mm wide welding lugs sticking out from bottom of exhaust which went through a couple of holes in the clamp, never seen that before.
Used a pair of plumbing pliers to squeeze the lugs flat then fitted new clamp, !5 mins tops.