I've not had this problem on your model of bike but I have dealt with several broken exhaust systems as you've described. You repair sounds good but you should ensure that the exhaust system fits properly and is not touching your bike where it shouldn't be. Many exhaust system breakages are due to fatigue caused by poor fitment.

Good advice, Chris. The flange ring is not welded to the header pipe on these bikes. It is silver soldered. Don't try bronze (brazing). It heat cracks really quickly.
Good Luck!

... if the solder joint is broken they can be redone. If the base metal is broken you may have to cut the pipe back, create new flanges, and have those brazed on. Use the lower melting temp brazing rod as Rick suggests.

don,t use bead blasting it embeds glass micro particles that really make it suck to weld clean with a 3 m pad and tig weld back on much stronger weld on face tig welding is very neat and the gasket will take up the imperfections

cheers
Andrew Cuttler