TY 250 mono exhaust packing?

[bird]

Can anyone explain the guts of the TY mono exhaust system for me? Front section: does this have some sort of packing inside to keep it quiet, and does it deteriorate over time? And if it's no good inside, can I cut the muffler open, replace the packing and reweld closed again? If that's the case at all. Same with the back alloy section: does it also have a packing that
needs replacing? My bike has a loud bark to it and I imagine that it should run quieter, which I'd like it to do. Appreciate any advice regarding the packing, replacement or steps to make the bike quieter. Many thanks.

[FM350]

Front box has anti resonance lining, consisting of a thin layer of packing material behind perforated sheet material.

Cant see how it would be possible to repack this, and you would probably be better to fit a perforated core to take up 75% of the exhaust, and fit packing around it, leaving other the 25% as an expansion area.

TY back boxes can be easily repacked..............just cut out a window in the back, remove and replace the packing, then pop rivet a cover piece back over the window, sealed with silicone.

[bird]

Thanks FM350. Second time you've helped me, much appreciated. I'll give your suggestions a go. Cheers.