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Thread: 1994 K75S speedo going wonky

  1. #1
    67-year-old Teenager indygt's Avatar
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    1994 K75S speedo going wonky

    The speedometer on my '94 k75S is malfunctioning. If I hit a bump, the speedo needle drops to zero and stops registering speed or odometer mileage until I hit another bump. The tach remains unaffected. Does this sound like anything I can fix, or is it a case for a BMW certified tech?
    Any diagnostic ideas?
    John M. Flora
    '03 K1200GT, '94 K75S
    MOA # 23538, RA # 16295, AMA Life Member
    Secret Squadron # SQ24418

  2. #2
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    Do the turn signals self cancel when the speedo is inop? If so, the final drive sensor and the connector near the rear brake resevoir are good. If not, the connector near the res. is probably poor. Both times my speedo quit, it was a dirty connector.

    If this doesn't fix it then check the connector that goes into the instrument pod.
    Ron

    91 K75RT ABS

  3. #3
    Kbiker BCKRider's Avatar
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    Quote Originally Posted by indygt View Post
    The speedometer on my '94 k75S is malfunctioning. If I hit a bump, the speedo needle drops to zero and stops registering speed or odometer mileage until I hit another bump. The tach remains unaffected. Does this sound like anything I can fix, or is it a case for a BMW certified tech?
    Any diagnostic ideas?
    A tip I got from this forum when the speedometer intermittently quit working on my 91 K100RS was to "remove and replace each of the fuses several times." To this day have no idea why that worked, but it has for several thousand miles. Even the mechanically challenged (like me) are capable of trying this trick, along with the previous one, before we start handing over the bucks. May be that a questionable contact with a fuse is moved by bumps in the road to cause your speedo to quit (or again start) working.

    Let us know how this works out.
    Doug
    1992 K100RS

  4. #4
    67-year-old Teenager indygt's Avatar
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    Narrowing it down

    I removed and replaced all fuses, then went for a ride on a bumpy road.
    I hit a bump less than a mile from home and the speedo dropped to zero, then revived briefly, then crapped out again.
    I rode for a couple of miles with the right turn signal on and the needle on zero and the signal never canceled itself. On the return trip, the speedo revived and another check of the turn signal cancelling showed it was working properly.
    Sooooo...
    It appears the problem is at the rear end of the cable.
    Not being a mechanic and not even sure what I'm looking at when I examine that part of the bike, is this something I can disconnect, clean and reconnect myself or is it beyond my meager abilities?
    (I'd be grateful if someone could provide a photo of the connection in question.)
    John M. Flora
    '03 K1200GT, '94 K75S
    MOA # 23538, RA # 16295, AMA Life Member
    Secret Squadron # SQ24418

  5. #5
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    The connection to clean is near the rear brake res. It is two wires -brown and yellow. Disconnect the connector and clean the contacts. I can't post photos here, Good luck.
    Ron

    91 K75RT ABS

  6. #6
    67-year-old Teenager indygt's Avatar
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    I pulled off the right side cover and quickly found the yellow and brown wires and their connector. I pulled them apart and sprayed them with some old Radio Shack contact cleaner, let them dry and reconnected them. A storm is upon us, so the test ride will have to wait until tomorrow morning.
    Thanks for the help, guys!
    Attached Images Attached Images
    John M. Flora
    '03 K1200GT, '94 K75S
    MOA # 23538, RA # 16295, AMA Life Member
    Secret Squadron # SQ24418

  7. #7
    67-year-old Teenager indygt's Avatar
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    By the way...

    Does anyone know what this connector is for? I noticed while I was fiddling with the speedo wires.
    Attached Images Attached Images
    John M. Flora
    '03 K1200GT, '94 K75S
    MOA # 23538, RA # 16295, AMA Life Member
    Secret Squadron # SQ24418

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    That is part of the ABS. There is supposed to be a blue cover clipped on it. You can reset the ABS light by grounding a terminal in that plug. The exact steps are on the IBMWR site, I believe.
    Ron

    91 K75RT ABS

  9. #9
    67-year-old Teenager indygt's Avatar
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    I rode down to the post office this morning - a distance of about three miles - and the speedo needle wavered a few times, but didn't drop to zero.
    After I collected our mail, I pulled the right side cover, disconnected the wires and reconnected them, making sure the connection was as solid as I could make it.
    Then I went for a 50-mile ride over a variety of surfaces. The speedo needle remained rock solid throughout.
    I think it's fixed.
    Thanks again for the guidance!
    John M. Flora
    '03 K1200GT, '94 K75S
    MOA # 23538, RA # 16295, AMA Life Member
    Secret Squadron # SQ24418

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