Thought I'd share this one - my CB550K3 RH pipes were rusted beyond help. Only No 3 is still available from David Silver so I needed a No4. I bought another No3, cut the silencer off, cut the old rusted No 4 silencer off the original No4.
Put the No4 downpipe on and bolted the new No3 silencer in the place of No4, tacked them together with the MIG then took them off and welded them properly. I now have a new No3 and No4. The No4 has a couple of rivets showing on the side as it has been twisted round but it's hardly noticeable and a BIG improvement on an old rusty silencer.
Luckily my LH pipes are fine...
