Installing an Acewell speedo/computer on an airhead --

Discussion in 'Airheads' started by bpeckm, Nov 23, 2009.

  1. MIOB

    MIOB Long timer

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    If make the grommet really warm (in boiling water?) won't it become flexible enough to slide it over your Acewell cable?




    Still enjoying my new Acewell 4454 a lot. It's a hughe upgrade from the already great 2853

    [​IMG]
  2. bill42

    bill42 Old-School BMWs

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    My later r100 was made with an electric tach. Somebody with more knowledge than me can probably tell you what factory plug you need. If not maybe check the fische on maxBMW.com and look at a 1981 airhead.
  3. craydds

    craydds Long timer

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    You may be thinking of the Acewell speedometer sensor. There is no Acewell cable in place of the stock tachometer cable. The BMW tach cable is removed, that is why I need to plug the hole.
  4. MIOB

    MIOB Long timer

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    Ok, sorry, misunderstood :1drink
  5. craydds

    craydds Long timer

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  6. pkboxer

    pkboxer Been here awhile

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    Snowbum says :Resistor discussion: Nearly any type of resistor may be used. It can be the old-fashioned type called 'carbon composition', or any modern type of 'film' or 'deposited carbon' type....or even a 'wire wound' type. The resistor value CAN be 470 ohms, but my tests indicate that 330 ohms is better.

    I have the resistor set up and didn't grasp exactly why it was needed...

    Until yesterday when i redid the wire and forgot the resitor.

    Bike started fine, ran fine. But wouldn't shut off. It was self energizing backwards from the charging circuit. :rofl
  7. MIOB

    MIOB Long timer

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  8. craydds

    craydds Long timer

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    Most of it seems to work:
    [​IMG]

    Got the settings entered:
    [​IMG]

    I entered 1480 mm tire circumference, per one (1) tire revolution "P-001". I will adjust this to get the correct speed, using my GPS for reference. For the "RPM SPC-X.X" I entered 2.0 for the number of engine rotations per signal; this seems logical but I don't know if it will work correctly. What is the correct entry? I will test it tomorrow for RPM and speedometer readings.
  9. bpeckm

    bpeckm Grin!

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    A lot of the final adjustments are trial and error, as you suggest...

    Airhead engines fire once every revolution (it sparks both sides at once, one is a "wasted" spark) but I wouldn't be positive which setting works... you will be able to tell when you start the engine, whether the tach is right, or at half- or double-speed!

    :D
  10. craydds

    craydds Long timer

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    Yeehaw! Fired it up. The tach works... at double the rpm. Re-entered the correct setting of 1 signal per revolution, started it up and the tach reads just right. bpeckm was right! It fires every rotation.
  11. Boxer Metal

    Boxer Metal Mad Scientist

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    I used this diagram to wire up my /6 and it worked great. The blue wire from the BMW harness I wired into one side of an aftermarket indicator light I found at the auto parts store and the other wire on the light I plugged into the extra green/black slot on the wire board inside the headlight bucket and the charge light worked great. I was able to find an indicator light that plugged right into one of the existing holes in the headlight bucket. The main hot lead/clock wire on the Acewell I ran to the red to the wire board. Everything works. Thank you for the diagram.
  12. craydds

    craydds Long timer

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    Cool! + 1 with thanks to bpeckm. Got mine all connected, everything works, except for the oil pressure light. Turns out that the oil pressure sending unit was not working. Easy test - touch the connection at the sending unit directly to ground on the engine case, the oil pressure lamp lights up (engine not running), connect to sending unit, no light. Ordered new sending unit. I have not tested the speedo yet. Maybe tomorrow. Again, many thanks to bpeckm and fellow inmates for their pioneering work.
  13. bpeckm

    bpeckm Grin!

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    Gotta say, these several YEARS after I wrote and posted that page, that it's a good feeling to have something work for a lotta folks.... I have gotten my share of 'hep' from inmates, and am glad that we can all share and pass around what we learn...

    Any day you learn something new is a good one! :evil



    :D
  14. tete

    tete clown shoes

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    im confused with a couple things here? I installed everything but a few wires.

    Blue is for gas, cap and hide. no problem there.

    Here is where im confused.

    the brown from the acewell goes to power for the clock. Well, my brown wire isn't connected and the clock is on and set

    so I coonected the brown to power (red) anyway and it still seems ok. what gives, is there any reason to have the brown wire from the acewell hooked up as my clock seems to be working anyway. Should I just cap and hide the brown or do I need to keep it connected for some reason I am not familiar with?

    Also with the turn signals do I connect them directly to the acewell or do I go to the fuse board thing

    I see that some people use the wires directly from the turn signal to the acewell. do they still blink properly etc? I thought they had to be connected to the relay?

    im confused and a noob at this.

    thanks
  15. craydds

    craydds Long timer

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    I assume you have the BMW green/black connected to Acewell red for power (+) when the key is ON, this would run the clock only with key ON.
    Acewell brown to BMW red is for unswitched power to keep your clock always on, even when the key is OFF. What happens when you turn off your key? Is your clock off?
    Turn signal leads from the Acewell could: 1) go into the headlight bucket and connect to the panel, Acewell orange to BMW blue/red (left turn), and Acewell white to BMW blue/black (right turn); 2) connect Acewell wires directly to BMW turn signal wires at turn signal lamps. You don't have to deal with the relay in any fashion. Look at post #320 for an example of wiring the Acewell turn signals wires directly to the BMW turn signal lamps; one could just as easily splice Acewell wires to BMW wires, or connect to the BMW fuse panel.
  16. tete

    tete clown shoes

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    I don't believe I have a green and black at this harness. Maybe the horn harness ? Ill have to chck but I'm pretty sure.
    [​IMG]
  17. craydds

    craydds Long timer

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    I think your green/blue is equivalent to my green/black. My bike is a '75 R90S and yours is a '75 R90/6, correct? There are some slight differences. I'll check my wiring diagrams.
    checked schematics, they show green/black and/or green/blue as positive (+) with the key ON
  18. craydds

    craydds Long timer

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  19. tete

    tete clown shoes

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    I have my acewell red connected to my grey w black stripe. So right now here is what I have left wire wise


    I have the black and white, blue and green w blue stripe [​IMG]
    On the ace well side I have white and the orange. I will connect these to the signals as commented earlier.
    [​IMG]
  20. tete

    tete clown shoes

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    Also of this is the case which power the additional indicator lamp for the generator, which a separate lamp all together if I am correct.