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Versions of Commando

Discussion in 'Norton Commando Motorcycles (Classic)' started by dynodave, Mar 21, 2019.

  1. dynodave

    dynodave

    Joined:
    May 28, 2003
    Been doing a tremendous amount of cross year parts compatibility across many early years.
    Had to categorize frames or I would go batty!
    LIKE...
    Gardern Gate plunger or swing arm
    LIKE
    Featherbed wideline or slimline chassis

    THEREFORE all Commando, which we know by it's name, means isolastic
    Plus
    early = TTR
    68-69-70= Two Tab-RCB
    Two tab is the steering stops. Two tab style was carried over from featherbed
    and Rear Cross Bar

    late = OTF
    71-75= One Tab-FCB
    One, central mount steering stop Tab, in the front of the steering neck... New style for late commando
    and Front Cross Bar & side stand mount
    71 pin side stand retainer instead of bolt side stand retainer otherwise same as remaining FCB family..

    The rolling chassis designation is totally separate from the power plant designation.

    More to follow:
     
    nortriubuell likes this.
  2. kommando

    kommando

    Joined:
    May 7, 2005
    The 71-75 needs to be split by headstock angle, trouble is measuring a 1 degree difference is problematical.
     
  3. dynodave

    dynodave

    Joined:
    May 28, 2003
    early = TTR
    Of primary significance:
    This series uses only fastback and "S"/central oil tank
    Rear cross bar center stand
    Late style slimline triple trees, therefore fork shroud or halo head light mount
    Interesting that front end matters, but who mentions that only in this group the fork offset is 2.25" carried over from the slimline.
    Lug nut rear wheel.
     
    Last edited: Mar 21, 2019
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  4. concours

    concours VIP MEMBER

    Joined:
    Dec 29, 2011
    Foxtrot
    Charley
    Bravo

     
    Last edited: Mar 21, 2019
  5. dynodave

    dynodave

    Joined:
    May 28, 2003
    If you allow me to define the commonalities first, then the differences will follow.

    late = OTF
    New triple trees for 750 offset 2.75" parallel
    850 triple tree average offset approximately the same but with -1 deg from parallel
    roadster oil tank
    cush drive :confused: rear wheel
     
    Last edited: Mar 21, 2019
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  6. APRRSV

    APRRSV VIP MEMBER

    Joined:
    Jun 26, 2016
    Thanks for this Dave. When you finish can you ask Jerry to put it in the Technical sticky?
    Ed
     
  7. dynodave

    dynodave

    Joined:
    May 28, 2003
    Ok since BB does not care for my terminology in an effort to make commando evolution understandable.

    Call the early = TTR = commando series 1 = S1

    Call the late = OTF = commando series 2 = S2

    S2 is 71-75 One, central mount steering stop Tab, in the front of the steering neck... New style for late commando and Front Cross Bar & side stand mount, all roadster oil tank, Imperial tubing VIN tag on left or Metric tubing VIN tag on right/different rear loop shape (Metric is mostly later in this series 73+750/850), cush drive :confused: rear wheel

    S2.A 27 deg New triple trees for 750 offset 2.75" parallel
    S2.A-1 1971 with pin side stand mount (often upgraded to bolt type side stand = S2.A)

    S2.B 28 deg, most are PN marked on LH tank mount, many rear loop supports extended by longer shock bracket, most are frame serial numbered on neck, 850 triple tree average offset approximately 2.75" but with -1 deg from parallel,

    S2.B-ES fork locking bracket, fixed G-box fixings, seat hinge fixing, MKIII cush drive rear hub.
     
    Last edited: Mar 22, 2019
    HRD likes this.
  8. dynodave

    dynodave

    Joined:
    May 28, 2003
    The 1949 Norton Heavy Twin went through many evolutionary steps even before the 1968 Commando. Both 500 and 600 had dynamo and alternator versions, 650 and 750 alternator only. However all commando 750/850 are the Desaxe version, which is where the piston bore grew only toward the rear to prevent interference problems with the cam/valve train.

    The common production NHT engine families,
    installed into the commando rolling chassis drive train series 1, 2A, 2B, 2B-ES, are:

    20M3
    20M3S
    200000
    300000
    325000+

    20M3: These are a twin chain timing chest carryover from the atlas with minor changes, rear points/coil

    20M3S: This is where the NHT changed to the single chain timing chest. Ignition is run off the end of the cam. Last series using the thick cam bushings.Twin and single chain are very substantially different and swapping parts require extreme familiarity and skill. There is even a bit of evolution within this family.

    200000 Combat Breather. First of the thin cam bushings. Original state of tune was unchanged with the same 28.5mm port heads, 1S cam and 8.9 compression as early commando. Very quickly it was given 10:1 high compression, hot rod 2S cam and 32mm big ports. I call it "combat tune". Combat tune was quite troublesome and production was reverted to standard tune, and two different heads were used for the completion of this series.

    300000 850 (828) bigger head bolt pattern, from the 750, and was offered with 30mm or 32mm ports, otherwise similar engine package form and fit as all earlier 750 commando engines.

    325000 MKIII Electric Start 850 (828) "similar" to 300000, but in reality it is very different in MANY ways. Not usable in earlier drive trains OR rolling chassis without a very significant amount of re-engineering.
     
    Last edited: Mar 23, 2019
    HRD likes this.
  9. C317414

    C317414

    Joined:
    Dec 17, 2017

    S2... JPN had VIN tag on the backbone, below the seat.
     
  10. 998cc

    998cc "Cheap" is rarely the least expensive. VIP MEMBER

    Joined:
    Oct 1, 2018
    Good Stuff dynodave!!

    ~998cc
     
  11. dynodave

    dynodave

    Joined:
    May 28, 2003
    Versions of Commando
    1.Catagorizing commando frames in to the general categories or series.

    2. NHT engine identification used in Commando

    NOW
    3. Body styles used and their relationship to the rolling chassis series and engine series.

    The following list is FAR from complete as to the finer details but in the end,
    is a commonly acknowledged identification of a unique end product of a Norton.

    Year of manufacture, MODEL YEAR, series of chassis, NHT drive train, and body style do not have consistant syncronization.

    These listed ID points are far from complete or all encompassing.

    S1:
    First Commando is self identifying as the original form... "Commando"

    With new models becoming listed, the S1 "Fastback" is now identified as a model

    "R" identification is wholesale commando/fastback with new tank and seat

    "S" New top triple tree, halo head light, high exhaust, new seat, new "S"/roadster gas tank, early side covers

    "Roadster" decaled in 70 only, only halo head light roadster, low pipes, first up-swept mufflers, early side covers

    End series 1 body styles

    S2:
    Roadster later, late side covers

    Fastback continues through S2A (72)

    LR fastback (early interstate)

    SS

    Interstate

    Hi Rider

    Interpol for police

    Other special model variants like "A" or lower production models like JPS are beyond the general beginnings that I am covering.
    They do however deserve coverage under a new discussion.
     
    Last edited: Mar 23, 2019
  12. concours

    concours VIP MEMBER

    Joined:
    Dec 29, 2011

    I kid.... I kid.....:p:p
    I am thankful for ALL the Norton knowledge that you not only have researched, learned seat of the pants & collected, but have chosen to SHARE!

    Did I mention building up a PERFECT CLUTCH the FIRST time, using your knowledge base?!?! :D:cool:
    Thanks Dave:)

    The Rambo thing was just a poke in the ribs, I’m always musing at the military’s propensity to coin/adopt new acronyms.

    Keep it all coming...
     
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  13. dynodave

    dynodave

    Joined:
    May 28, 2003
    I pretty much convinced myself there was value for norton enthusiasts to know about specific versions of commando.
    One example where it might have paid off for the designer of this product (and the buyers).
    Here is an item built specifically for a S2-OTF using the front yoke tube as the mount and the problem of a ?marginal design or installation.
    https://www.accessnorton.com/NortonCommando/old-britts-oil-pressure-gage.27412/

    Consider another design that would be for both S1-TTR and S2-OTF which is mounted in the steering lock hole on both styles of upper triple tree. A 1/8 nylon flex line runs with the cables and wiring with no dents in the fender. One top mounted polished stainless bolt head for quick and easy removal when needed.
    [​IMG]
    [​IMG]
    Worked flawlessly and held in place rock steady for 12K miles in Roadster, Fastback and Hi Rider and Dunstall configuration of my combat(above).
    Also shown in friends S1-TTR 70 "S" clone currently being built (below).
    Moved from one bike to the other in less than 2 minutes. Normally would take longer.
    Can't say I ever needed or used a steering lock on any bike...ever...
     
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