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Thread: 1913 Harley twin engine

  1. #21
    jurassic Guest

    Default 11 twin

    i think it is safe to say that those cylinders on your engine came from the factory with those the pristine vin numbers on both seem to show.some people in this forum would like you to believe that the factory saved their major changes till jan. 1st. , but any of us who have ever played with vintage bikes knows that is not the case.especially with the twin engine ,which was in a constant state of development.the question is ,why did they change their entire cylinder mold,mid year.?what was going on in that combustion chamber that made the engineers decide to change the angle of the spark plug?or?do all 1911 twins in existance today have the 45 degree angle plugs ,and the drawings we are looking at are only renderings from the factory that were put out early on before they actually put the 1911 twin into production.i have photos of the original paint 1911 that was at oley,no 90 degree plugs,also on bruce linsdays 1911 ,no 90 degree plugs.same with chandlers.bottom line,you got a 1911 twin,that should be taken off the floor of the garage and put back on two wheels.even if that means buying a replica chassis.congratulations on scoring this fine piece of harley history.

  2. #22
    jurassic Guest

    Default 11 twin

    just to note ,notice that the intake rockers on ross's engine have adjustment screws like indian,which the other 11 twins dont have.also notice that there is an oil line pluged into the front cylinder,the other 11 twins have this,but i dont think 1912 also appears that the rear exhaust port on this engine is broken out,which will be a difficult also looks like the sprocket shaft originally came extra long,as most stationary engines do.

  3. #23
    AdminGuy Guest


    I think they figured out that 45 degree angle worked better and changed mid year. Looks obvious to me. I'd be thankful that your 1911 has the 45 degree angle which makes it a much better runner in my mind. I feel it is correct.

    It's sooooooo... cool Ross. Here is my request. When you paint it -could stay away from that super glossy look. That just kills it for me.

    And use the black tires for the road runs. White is for show.
    Fond memories of the Smith clan rideing around.

    We have a simular engine kicking around my hood. Going to have to take a closer look at it now. I think it's a little later.

  4. #24
    B. Rodencal Guest


    When I first saw a pic of this engine many moons ago, It was kind of dark and hanging on a wall. Ross's pics are very nice. the numbers are great. I agree with the oil line fitting, '12 does not have the fitting. I would concour that it is a '11 after spending some time looking at it. It is in really nice shape, and i too would love to hear it run again! Congrats!

  5. #25
    HarleyCreation Guest

    Default 1911 "A" Serial Numbers

    Originally posted by silentgreyfello
    Hi Ross,

    I stand corrected on my earlier vin number post...

    I have two books, "Harley Davidson Motor Company" by David Wright and "Harley Davidson, the Milwaukee Marvel" by Harry Sucher that both say 1911 should have a vin of 7600-10000 followed by an A.

    I just checked some more photos and notes of number-matching 1911 bikes and none of them fit the above description.

    1911 single: 8887
    1911 single: 9325
    1911 single: 9588
    This twin motor: 304A
    1911 twin (Chandler): 922A
    1911 single: 1815A

    See a pattern? Perhaps the 1911 numbering system went like this:

    7600-9999 without the A, then they went to 100A and up. Just a theory without any paper facts.
    Actually, your theory is backed up by "paper" evidence.

    The info in Sucher's book about how to read 1911 "A" numbers is misleading.

    On a Factory chart compiled in 1927 it states the following about the 1911 serial numbering system and I quote exactly here (emphasis mine):

    "7000 to 10,000 and all numbers followed by letter A only."

    That better fits your theory of the run of 7000 thru 10,000 without an "A" and then Harley started over with a run of "A" numbers.

    This is also backed up by other 1911 records (MC Regs.) that clearly show numbers in the 7000 range on the road by the fall of 1910 rising into the 9000 range by April of 1911. The first "A" numbers (196A & 435A), both singles, also appear by April of 1911. The first "A" twin (922A) shows up in May of 1911.

    From this it would appear that 304A was built in early (Feb?/March?) of 1911.

    Just where the "A" numbers started I'm not sure as the lowest so far seems to be "169A," but 100A is a good guess.

    Not sure how the spark plug change fits into this sequence...

    Jeez, I just noticed the Chandler Twin you listed is 922A.

    What an interesting coincidence!

  6. #26
    Ross Guest


    Awesome info so far. Hey Harley Creation is any of your original info something that could be scanned and shared on the post? I think I can safely say I have a 1911 motor and I am beginning to beleive that the 90 degree plugs were only in advertising literature not on the actual bikes when they went into production. I guess that theory could be challenged with the first person to produce a REAL photo and not an artist's rendition of a head with a 90 degree plug. Now my big challenge will be to hook up with the right people to buy frames etc.I believe we will begin the process to do a repro restoration not a racer.Anyone who knows me knows I like to ride what I own.Any help would be appreciated. Our last project was the world land speed record in2005 at Bonneville. You see more at

  7. #27
    HarleyCreation Guest



    Good luck with your project. That's a nice year to own. Somewhere I think I have the number of twins made in 1911.

    I have a photocopy of the 1927 Factory chart. The SN data is transcribed from hand-written records into a couple of notebooks. It's useful information if used with caution.

    For example, I looked some more for low "A" numbers in 1911 wondering where they began (100A?) and came up with the following.

    I found several "A" numbers in the 100-200 range (103A, 104A, 111A, 137A, 169A) but only 1 in the 0-99 range (22A).

    Because these old records were carelessly written (guys even made trick or funny entries!) I view the "22A" number with some scepticism and would tend to leave it out of the sample until we can verify additional 0-99A numbers.

  8. #28
    Ross Guest


    Thankyou HC. Your help and extensive knowledge is much appreciated. By the way I am very impressed with how helpful this forum can be. Hats of to you President Pete and all your helpers.

  9. #29
    AdminGuy Guest


    Well -thanks for shareing Ross. Very cool stuff!

    The other old HD twin engine was just a 1915. My mistake.

    A big thanks to all the guys that participate on this club board.

  10. #30
    martin Guest


    Yeah, that's it... just put the motor in a reprod frame and call it real... Thats what Competition does. Folks getting wise to that though. Another guy right here in Ohio going to do the same thing to an '11 twin motor... aint that right, DM? Then pass it as reel.

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