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Help identifying g15cs

Discussion in 'AJS & Matchless' started by Ian millard, Dec 24, 2019.

  1. Ian millard

    Ian millard

    Joined:
    Dec 23, 2019
    hello everyone just joined the forum
    I have recently bought a matchless in bits
    The frame number is a75554
    Chassis number starts g15cs109080m2
    It’s suppose to be a pre production scramble version
    It has the small tank upswept pipes knobbly tyres
    It’s always been in the uk
    Can anyone shed any light on this for me
    Thanks for any help
    Ian
     
  2. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    Ian,

    It seems you have a 1961 G12 frame and a 1963/4 G15Mk2 engine. If the frame number is genuine, I doubt the frame is a pre-production version. Why would the factory use a 2 year old frame, which has the wrong headstock? Beyond all, the G15 engine doesn't line up with a G12 frame.

    Of course it's possible someone re-stamped a G15 frame for obscure reasons. This was certainly not done by the factory.
    Have you tried to mate the engine and frame using the proper engine plates?
    A75554 G12 would be stamped at the right downtube below the headstock. A G15 frame would be stamped at the left downtube below the headstock.

    -Knut
     
  3. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Hi Knut.
    As i can see from my bikes, there are not main differences between G12 (the later type already with roadholder forks and Norton wheels) and G15 frames.
    Could 75554 not be a G12 frame?
    I have a part a 86783 frame (ii dont know from were it comes) that could seem the same of G15 (has a later swinging arm for Norton wheel) but has the main difference to have the right bottom lug larger than G15 so that you canot line up the engine plates without cutting first this lug.
    Piero
     
    Last edited: Dec 30, 2019
  4. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Hi.
    My G15 has frame 10983. and engine G15CS/10983. M2 that means it is a 1964 MK2.
    This type had large thank with great alu badges, both large ribbed fenders, large dual seat, and lower pipes.
    Has your swinging arm the rounded join to accomodate the Norton rear wheel or is it stright like early type?
    Swept back pipes were fitted on G15 CSR type, not CS.
    Ask to Knut, he knows every thing, he is an autority.
    Piero
     
    Last edited: Dec 30, 2019
  5. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    The G15 frame is indeed a development of the 1964 G12 frame (and the G3/G80, for that matter). If A75554 is a legitimate stamping, it can´t be a 1964-on frame.

    Your frame with serial no. A86783 is probably a late model G12 frame. While I have never compared the last model G12 and G15 frames one to one, two or four front lugs will be positioned differently and stud bolt sizes may differ as well.

    Edit: Going by the pictures received, the frame number as without the prefix 'A' and the number is stamped in the wrong place. Indeed, frame no. 86783 belongs to a late 1952 model.
    http://archives.jampot.dk/general/Matchless_Frame_Numbers_1950-1966_AJSMOC.pdf
    Now, that can't be since technically the frame corresponds to a 1964-66 duplex frame, with provision for Roadholder forks and a swinging arm to take a Norton rear wheel. Therefore, I suspect the bike was stolen and the frame re-stamped to make it "road legal".
    It would be interesting trying to recover the genuine frame number!

    -Knut
     
    Last edited: Dec 31, 2019
  6. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    Hi Ian,

    What´s the difference between a frame and a chassis, in your book? I took "chassis number" to be engine number stamping.

    -Knut
     
  7. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Hi Knut.
    I think that 86783 could be a 1965 G3 or G80.
    The larger right bottom frame stud lug is not compatible with a twin engine.
    Piero
     
    Last edited: Dec 30, 2019
  8. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    Possibly. The frame was manufactured in the june-august 1964 time span, prior to the 1965 models.
    Matchless roadster frame numbers were used for both AJS & Matchless, as well as type of machine (single / twin engine).
    Meaning your frame could be for a single and the lugs differed from those used on the twins, AFAIK.
    It´s necessary to look up the dispatch records to verify which type of machine the frame was made for.

    Edit: See #5 for new information pertaining this frame.

    -Knut
     
    Last edited: Dec 31, 2019
  9. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Yes
     
  10. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    AJS & Matchless Owners Club: Machine Dating Request says that 86783 is a 1952 G3L.
     
  11. kommando

    kommando

    Joined:
    May 7, 2005
    In UK DVLA language the frame number is the chassis number and the engine number is the engine number.
     

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