| mono sub assembly
Wave, looks like where its broken is caused by the weight of the exhaust as your weight is applied to the sub frame at the other side of that weld. The exhaust is bolted onto the subframe with one very big bolt at the back and two smaller bolts closer to your bum.
It was a common fault on 03/04 bikes that the alloy around the big bolt would snap at the weld to the subframe.My mate nearly crashed his 03 749S when the exhaust fell onto his rear tyre at high speed. Ducati did a superb repair under warranty.
How olds the bike can you get it sorted under warranty?
If your getting it welded I would get some extra strengthening added as some alloys become soft as cheese when theyve been welded up. | 
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