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What do I have?

Discussion in 'Norton Commando Motorcycles (Classic)' started by novadose74, Jun 17, 2018.

  1. novadose74

    novadose74

    Joined:
    Apr 25, 2012
    Here’s the number on the block. The tranny has the same number with what looks like the letter “M” stamped at the end. ANY help would be EXTREMELY helpful. Thanks. Tom
    Well, I forgot how to post a pic. Anyway the number on the block is; 221508.
    Agin, ANY help would be great. Tom
     
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  2. Time Warp

    Time Warp .......back to the 70's. VIP MEMBER

    Joined:
    Dec 3, 2012
  3. Robert_Norton

    Robert_Norton

    Joined:
    Dec 21, 2008


    Just going by the serial number you've provided, it should be a 750, a 1973, I believe, and will not be a Combat model. Are there markings stamped in the head? Anything over the right side exhaust valve cover? Is there a "C" stamped on the top of the head?

    If it's in pieces, or when it is, you'll want to research the possible modifications to the inside of the cases, in order to improve oil flow. I don't have the expertise to tell you what the correct modification(s) are, just that there are some modifications for 750 cases, that many members here recommend be done.

    Figure out how to post some photos online so the bike can be viewed.


    .
     
  4. novadose74

    novadose74

    Joined:
    Apr 25, 2012
    Thanks. I’ll check over the exhaust. Tom
     
  5. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
  6. Atlas Commando

    Atlas Commando VIP MEMBER

    Joined:
    Feb 27, 2018
    That link is a great reference. It appears I have a very early Combat based on the numbers.
     
  7. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    I have no records to rely upon but I do have a hypotesis. In true AMC fashion, the postfix letter indicates the final drive sprocket size, and 'M' probably indicates a 21T sprocket. Postfix 'N' would indicate a 19T sprocket, as found in 650/750 Dommies.

    -Knut
     
    Last edited: Jun 19, 2018
  8. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    And C, G, K, L, S, Y?


    "SERVICE RELEASE motorcycles No: N.25 November 1970
    .......etc.......
    Identifying marks on assemblies.
    Worldwide (Trade Only)
    From queries received we gather that our system of stamping a Factory identification symbol on certain assemblies (for example: the marking "X" on the top of the rear engine mounting boss) is causing some confusion.

    We respectfully point out that such markings are purely a Factory Facility to enable us to keep track of any production changes without the need for stripping. Such markings will appear only for a limited time and then disappear whereas the feature may well continue. As such, we shall only make known the purpose of markings where we feel common knowledge is mutually advantageous........etc."
     
  9. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    No contradiction to what I wrote, Les. However, the letters you refer to are no postfix letters but rather separate indentification letters. Thanks for citing the service release.

    -Knut
     
  10. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    Well, I've yet to see an example of a Commando gearbox where the letter is not stamped separate from the number.

    If a letter supposedly denoted factory sprocket size then logically all Commando gearbox serial numbers would include a letter, however, the vast majority have no letter marking.
     
    Last edited: Jun 19, 2018
  11. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    Good point!
     
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