Last year when I checked, part number 18391-390-000 was discontinued. It is a 'gasket' that seals between the 4 into 1 header and the silencer on the CB550F.
Mine is long gone, and who knows what is there now - some ugly wrapping of some sort not doing the job. Anyone have suggestions on what to use in place of the original Honda part?
Service Honda has it as discontinued as well unfortunately, so any thoughts would be welcomed.