Installing an Acewell speedo/computer on an airhead --

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

  1. Dave-d

    Dave-d Adventurer

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    I have an R90 with the S-11 sensor with the 34/11 rear gears and I found that 1480 worked out within about 3 mph over my GPS at 65mph.

    Dave

  2. some_guy

    some_guy Been here awhile

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    Thanks. I had 2001 in there. somehow thats what i came up with. was about twice my actual speed judging by traffic. so i halved it. seemed to be about 15 under then. howd you come up 1480?

    edit:33/11 final drive on mine so its probably different. defiantly gets me closer though.
  3. Dave-d

    Dave-d Adventurer

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    Fair warning, I am a geek....I took the formula from Snowbum's page, figured out what the speed would be equal to at 3500 RPM, and then checked where the speedo read from there. After making adjustments until it was a couple mph high, my wife suggested that I toss a GPS in my tank bag and check my work......she is the smart one in this marriage, I guess......:roflIf my math holds up, you would be about 2 mph lower than mine.

    Dave
  4. some_guy

    some_guy Been here awhile

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    i didnt know he had a page on the subject..,will be looking for that. Thanks again!
  5. Dave-d

    Dave-d Adventurer

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  6. some_guy

    some_guy Been here awhile

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    If i'm understanding that right, and my initial measurement of 2001mm was right, my setting should be 1382. I'll try that out tomorrow.
  7. yellowbirdrs

    yellowbirdrs Been here awhile

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    Did my headlight eras as well. Also install a tachometer in the bucket hole not an Acwell.

    [​IMG]
    [​IMG]

    Sent from my iPad using Tapatalk HD
  8. tete

    tete clown shoes

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    Anyone care to share with me how they wired the s-11 sensor?

    This would be a HUGE help to me. Also is everyone simply using high temp grease in the tachometer cable hole in the front of the engine?

    Thanks

    T
  9. some_guy

    some_guy Been here awhile

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    there was no wiring for me. the connector on the sensor plugged into the connector on the speedo.
  10. tete

    tete clown shoes

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    I tried that and got no signal. Hmmmmmm .....
  11. photorider

    photorider Been here awhile

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    It should just plug in. Check all your grounds. There are several if I remember correctly...
  12. bill42

    bill42 Old-School BMWs

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    OK so I bought my acewell well over a year ago and finally yesterday I took the plunge and wired her up. I totally understand why I can't use the hazard light indicator in the gauge as a charge light. I'll be mounting an LED in the headlight bucket with a load resistor. What I can't wrap my head around is the directional marker lights in the Acewell. Bpeckm's original chart mentions that you need to go inside the bucket to find the separate leads since the factory gauges use a single direction indicator light. But on his chart he also mentions the 2 BMW wires that are distinct left and right directional leads. So if the separate wires exist why do I need to tap into the headlight bucket? I know the flasher is in the bucket and that must provide the blinking on/off positive lead for both directionals but if there is only a single directional light in the factory gauge unit, why were there 2 separate left/right wires from the factory harness going into the factory gauge cluster?
    I did try to hook up to the factory wires but nothing worked probably because I have no actual direction lights wired up yet and the flasher probably needs a load to make it work.

    I hope someone remembers this!
  13. some_guy

    some_guy Been here awhile

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    What year/model bike? My 95 R100RT had two separate leads in the harness for left and right indicators, but the diagrams for older bikes didn't appear to have two.

    The indicators should still work without any bulbs hooked up, will just flash faster. The fast flashing is really why you need a resistor for the LED lights.
  14. bill42

    bill42 Old-School BMWs

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    Ah, so maybe that's it. I have an '81 R100RT. I have the Blue/red and the blue/black harness wires going into the factory gauge cluster. I believe you are telling me that I do not have to tap into the headlight bucket. The RT even has a non-switched full-time power lead for the clock which is nice.
    I also bought an LED flasher unit to replace the stock flasher since I am using LED directionals. So i'm going into the bucket just to swap that out and to install my gen light.
    thanks!
  15. r60man

    r60man Been here awhile

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    This should be the solution to my issue. Both my Speedo and Tach have died on my R75/6. I am going to give the bike a good look over as it has Lester Mag wheels on it to make sure I can mount the sensor and magnet. Thanks for all of the info in this post!
  16. bill42

    bill42 Old-School BMWs

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    No need to use a magnetic pick-up anymore as you can now buy an airhead-compatible speedo sensor that plugs right into the transmission feed of the stock speedo cable.
  17. bpeckm

    bpeckm Grin!

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    The early bikes (from which I made the original sketch and wiring diagram) had an indicator "signal" that went from the actual flasher to that light, and THEN to the left-or-right selector switch. If you have a red/blue and a black/blue available, they are the correct, (separated) left and rights that can be hooked up to the Acewell.

    BMW's wiring harnesses evolved over the years from fairly simple to more complicated!

    :D
  18. some_guy

    some_guy Been here awhile

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    I thought the harness on my 95 was pretty simple. I see pictures of rats nests in headlight buckets and I'm kinda glad my bike is so new.
  19. bpeckm

    bpeckm Grin!

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    The "old" bikes did all of the connections in the headlight bucket, on that circuit board.... it looks awful, but once you understood it, was really very simple, indeed...!! And the headlight bucket need not be a rat's nest!

    [​IMG]


    Later bikes did most of the connections and relays under the tank... looks simple cuz the connections are all done with multiple-pin connections.

    [​IMG]

    In the grand scheme of things, and especially when you compare to today's BUS systems and wiring harnesses, they are pretty durn simple!!

    :D
  20. chasemotorman

    chasemotorman Adventurer

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    Can you provide a name or details of said sensor?