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(engine) exhaust mounting hardware - flared adapter for header pipe - ???

Discussion in 'Norton Commando Motorcycles (Classic)' started by joe czech, Dec 13, 2019.

  1. joe czech

    joe czech

    Joined:
    Feb 21, 2019
    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.
     
  2. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    The sealing washer is not used with the spherical seating and flared pipes.
    https://andover-norton.co.uk/en/shop-details/16482/ex-pipe-spherical-seating

    Although supposedly Mk3, that type of flared exhaust pipe was introduced on the Mk2A.

    The flared pipes (065256 & 065257 same as 850 Mk3) are listed in the Mk2/2A supplement for Mk2A but the spherical seatings and spherical collets (065259 & 065260) appear to have been left out.

    https://andover-norton.co.uk/en/shop-details/20631/exhaust-pipes-pair-850mk3-balanced
     
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  3. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Interesting. My MKII did not have the spherical seating washers, just the short rose nuts, collets and copper sealing rings. This was on the balance-pipe headers when I removed to replace with un-balanced headers after finding the left side "branch" cracked (as is typical). What is the purpose of the spherical seats and are the pipe flanges a different shape for their use?
     
  4. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    Listed for Mk2A, not Mk2.
     
  5. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    OP: If the un-balanced headers you're planning to substitute in do not have the flared ends, then leave out the spherical seating rings and the collets, and use two sealing washers (the steel type since these compress less) per header pipe if you want to keep using the shorter rose nuts (or buy the longer/earlier (prior to MKII) thread type).
     
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  6. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    nortriubuell likes this.
  7. joe czech

    joe czech

    Joined:
    Feb 21, 2019
    that clears up many things. seems somewhere along the line, someone added the sealing washer in with the spherical seal. most likely the reason why the finned exhaust nuts are not threading in all the way. BTW, you are a wealth of information! thanks....
     
    Last edited: Dec 13, 2019
  8. maylar

    maylar VIP MEMBER

    Joined:
    May 13, 2007
    I found out the hard way that the short 850 nuts don't work with 750 pipes, they bottom out. You can double up on the crush washers, but I found longer ones on eBay somewhere in the same style.
     
  9. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Yes I wanted to use longer roses but when I went to fit them I discovered a DPO had machined the head to take not only oversized diameter roses but also lefthand threaded!! So mine are basically custom Unobtanium.
     
  10. maylar

    maylar VIP MEMBER

    Joined:
    May 13, 2007
    That's just... wrong.
    So, are you lining up for one of Fullauto's heads? ;)
     
  11. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Not bloody likely ;-)
    But may be sending the RH10 head off to Mr. C. for rejuvenation one day and see if he can return it to normality...
     
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  12. concours

    concours VIP MEMBER

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    Dec 29, 2011
  13. olympus

    olympus

    Joined:
    Aug 5, 2017
    Are these spherical collars fitted tapered face to head or down pipe??
     
  14. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    Taper (spherical side) to the pipe. Edit: Assuming "collar" refers to the spherical seating and not 'collets' which can only fit one way.
     
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  15. olympus

    olympus

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    Aug 5, 2017
  16. maylar

    maylar VIP MEMBER

    Joined:
    May 13, 2007
  17. dynodave

    dynodave

    Joined:
    May 28, 2003
  18. Ron L

    Ron L VIP MEMBER

    Joined:
    Feb 27, 2004
    I have always used the collets from the '73-'74 850 (06-3990) along with the sealing washers with the 850 nuts for non-balanced flanged pipes. Or just the sealing washers with 750 nuts.
     
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  19. river700

    river700 VIP MEMBER

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    Dec 25, 2010
  20. maylar

    maylar VIP MEMBER

    Joined:
    May 13, 2007
    They're thicker, only one per pipe is needed.
     

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