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Cam Chain Tensioner Question

Discussion in 'Norton Commando Motorcycles (Classic)' started by swooshdave, Jul 11, 2019.

  1. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009


    Someone pointed out that the cam chain tensioner plate, the thinner outer one, should be upside down. Does anyone know why. I don’t see an obvious advance.
     
    Last edited: Jul 11, 2019
  2. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    "CST Journey to nowhere - fishing" video. :confused:


    Outer is thicker.
    Both should be fitted the correct way up.
    Inner, long end down, outer long end up.

    I think because if the outer thicker plate is fitted long end down it limts the range of tensioner adjustment?
     
  3. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    Yes, thinner one goes inside. I just don't see where the plate orientation is different in the manual for the two plates.
     
  4. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    As I said, if the outer is fitted long end down I'm sure it would restrict the tensioner adjustment, especially the rubber covered tensioner.
    [​IMG]
    [​IMG]
     
    nortriubuell likes this.
  5. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    I wonder if that's a MkIII thing. No rubber on the earlier tensioners, I believe.
     
  6. Anglophile

    Anglophile

    Joined:
    Mar 6, 2010
    My '71 has rubber on the tensioner.
     
  7. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    No, as it's in the pre-Mk3 manual and I think the outer plate fitted long end down would still restrict adjustment whether it was the rubber faced type or not.

    The 06-4647 rubber faced tensioner was introduced on (or sometime before?) the 850 Mk1A and also fitted to 850 Mk2/2A.
     
  8. Fast Eddie

    Fast Eddie VIP MEMBER

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    Oct 4, 2013
    Well I’ve never understood the ‘one plate up and one plate down’ logic either !
     
  9. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    Then maybe it's 750. I saw an earlier manual (with the magneto) and it said the plates were on the same. Also keep in mind that the manuals will always refer to the latest models.
     
  10. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    What's right for a 'magneto' model isn't necessarily right for a Commando.
    Factory pre-Mk3 manual, Clymer manual, Mick Hemmings in his video all say outer plate long end up.
     
  11. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    Pre-MkIII as in 850 or 750? Again, all of those guides are meant to address the latest models.

    https://www.manualslib.com/manual/1013224/Norton-Commando.html?page=27#manual

    See Paragraph 10.

    I feel like bible study and having to quote scripture from King James when everyone else has the Modern...
     
  12. Ron L

    Ron L VIP MEMBER

    Joined:
    Feb 27, 2004
    As does the factory pre-Commando manual for 88, 99, 650 SS, Atlas, and G15
     
  13. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    Then what is the manual that I linked to from? And do you see where it doesn't mention the plate orientation? Am I missing something?
     
  14. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    Pre-Mk3 manual is for all models "from 1970" (to 1973) and the manual you should have been referring to and not the '68-'69 manual.
    http://www.classicbike.biz/Norton/Repair/70up_Commando/70upCommando.pdf

    I have that manual and para. 10 only mentions fitting the inner plate long end down.
    On an adjacent page there is a photo showing the outer plate fitted long end up.

    [​IMG]

    Sorry to say it, but it sounds like you are trying to justify fitting the plate the wrong way up as the information IS in section C30, 7 of the appropriate manual.
     
  15. Ron L

    Ron L VIP MEMBER

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    Feb 27, 2004
    Seriously? You are asking us what manual YOU linked? For clarification it does mention that the inner plate long end goes down. It just does not mention which direction the outer plate fits.

    Oh, and that is the 1969 Commando manual.
     
  16. Ron L

    Ron L VIP MEMBER

    Joined:
    Feb 27, 2004
    Interesting side note I just discovered. The slipper/adjuster for the two chain engine and one chain engines are different. I never noticed this before. The orientation of the slot is different. Luckily, I didn't mix up the timing chest components of the P11's and '68 Commando with the later ones.
     
  17. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    Mick H. mentions that in his video and I'm sure you would have soon noticed if you'd tried to fit the wrong tensioner.
     
  18. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    More questioning the "why it makes a difference" aspect. I have my suspicions but would like to hear other people's opinions.

    If your opinion is "because it says so" kindly let me know how tight your clutch nut is at...
     
  19. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004

    Well, I can only suggest you go back to my first (and second :rolleyes:) reply as to why it makes a difference, however, that's just my opinion.
     
    Ron L likes this.
  20. swooshdave

    swooshdave

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    Apr 15, 2009
    Totally agree with that.
     

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