on my 74 Mk2 header pipe (engine side) - the end is flared (35-45° - ???). part of the mounting hardware is a flared adapter ring that mates to the flared end of the pipe and the other side, a flat end that mates to the sealing ring/washer. the rest is the standard split collet/exhaust nut. question - I don't see the flared adapter ring in the parts book. so not original? missing from the parts book? a Mk3 or Mk2a feature? or what? does the flared adapter replace the sealing washer? i'm thinking I have too few threads engaging on the finned exhaust nuts to cylinder head. too many parts? little confused. this is the way the bike was assembled when I bought it, although can't trust the previous assembled configuration. TIA.... i'd post a pic, but don't have the pipes off the bike just yet.