'51 R51/3 Ignition Terminal Questions...

Discussion in 'Airheads' started by Tracknod, Oct 8, 2012.

  1. Tracknod

    Tracknod Been here awhile

    Joined:
    Apr 10, 2006
    Oddometer:
    345
    Location:
    Home of the Rat in Fl :(
    Hello All,

    I am trying to rewire My R51/3 and am running into a problem. First off, I am using the correct manual which has this Hi Res wiring Diagram:


    This is basically a higher res image of a diagram off Duane's site of this:

    [​IMG]


    Here is my board in my new bucket:

    [​IMG]

    Now everything is connected, except my two questions.

    What is terminal 57 and if what I pointed too is it, like in Duane's image suggests, how do you connect to that? Terminal 56 has a wire connected to the underside of the board that is going to the dimmer/horn switch, is there supposed to be a wire connected to the not labeled terminal in a similar fashion?

    The board is in a replacement headlight from S. Meyer in Germany. My original board in my bucket was broken in half and would kill the bike if I hit a bump causing me to have to open the shell and fiddle with it which became a pain.

    It is the same replacement board that they sell.

    On my original cracked board from '51, the previous owner soldered some spade ends to 57(???) and 56. Notice 57 isn't labeled here either:

    [​IMG]

    [​IMG]

    Should I just solder a wire in the terminal? It does get power when the switch is turned. It would seem that this is for a flat head screwdriver, but the terminal just turns.

    Also, What is that light grey wire that looks to be soldered to 30/51 and what does it attach too?? It is in every picture I can see from replacement boards i have found online including Max's site. Is this for later bikes?


    Thanks in advance...

    Shane
    #1
  2. Tracknod

    Tracknod Been here awhile

    Joined:
    Apr 10, 2006
    Oddometer:
    345
    Location:
    Home of the Rat in Fl :(
    Ok...

    The /2 Guru Vech came through and answered my question that I cross posted on the /2 list.

    Here is his reply:



    So there is the answer in case anyone ever needs it. Search little google bots, search.
    #2
  3. bmwhacker

    bmwhacker Still on 3 wheels

    Joined:
    May 6, 2009
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    4,647
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    MONTANA NATIVE from NATIVE MONTANA
    I can't believe that the hundreds of 1951 R51/3 owners around here aren't speaking up? :eek1
    #3
  4. Tracknod

    Tracknod Been here awhile

    Joined:
    Apr 10, 2006
    Oddometer:
    345
    Location:
    Home of the Rat in Fl :(
    LOL... Well it is practically the same board that would be on any 2 cylinder BMW from 51-69 so I figured someone might know. :wink::D I mean that is a couple hundred thousand bikes. That covers R51/3, R67/1/2/3, R68, R50, R69, R60, R50S, R69s/, R60/2, R50/2 and probably almost identical to all the singles as well....
    #4
  5. Bill Harris

    Bill Harris Confirmed Curmudgeon

    Joined:
    Sep 20, 2008
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    backwoods Alabama
    Heck, almost that same board is used on the /5. I guessed pretty much the same thing that Vech advised, but since I din't know fer sure, I kept quiet. I imagine that the PO soldered to 1/4" female fastons to the two "slotted" posts to keep from having to solder in such close quarters. Not a bad idea, IMO.

    It is so BMW-esque that they used the same board through the /5 years. Even down to the not-ever-used Terminal 2, the "magneto kill" ground contact. The board in my /5 is almost 40 years old and has been removed, repaired or refurbished 3 times, with the aid of a junk donor-board.
    #5