Looks to me that the rust out is at the low point where the condensation could've puddled if pipe was on a bike that had way too many short trips where condensation wasn't burned out. That pipe could've been on other bikes before yours, as the seat looks like a CB500T (twin) and tank doesn't look correct (sits oddly). Yes it pretty "worn" but you can rig it up to get by or even run it as is!(loud?) Avoid short trips, they will continue to feed the rust with water. I have bought used inexpensive & very good condition Jardine slip-ons that go on the cut off original head pipes (4 into 2 style) $50-$75 incl. shipping on ebay.
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CB75OK6, CB550K6, CB500K2
its great you said that about the seat. i thought it was kinda weird looking too. i thought the 75 cb550 seats where more horizontal and didnt have that weird bottom bump.
well its the headers that are messed up that kerker tip still looks good.
and this bike will be used for short trips..... home to school like 1-2 miles
never head the bike running so i dont know if its super loud
