Results 1 to 12 of 12

Thread: 92 K75RT speedometer flakey ..

  1. #1
    Registered User scoobs's Avatar
    Join Date
    Jun 2008
    Location
    Columbus,GA
    Posts
    250

    Thumbs down 92 K75RT speedometer flakey ..

    My speedometer has started acting up, I hit around 45mph @ 4000 rpm and the needle starts to drop off to zero. It doesn't seem to be rpm related as I can tool along at 4000 revs in any gear with no problems, but once I hit 40-45 mph then it all goes pear shaped. I thought the sensor might be going out, as this has happened in the past. Normally just pulling it and cleaning the excess oil off fixes the problem, but it didn't work this time so I replaced the sensor.
    Dang thing failed on me 15 miles after starting a "Bun burner 1500" this morning so I had to return home- I could have surived without a speed readout and relied on GPS but the sensor also feeds the odometer/trip meter so I'm stuck.
    The wiring and connections appear to be okay, bike has around 125,000 miles on it.
    as usual any help greatly appreciated,
    Ian.
    Ian Robert "Scoobs" Scobie

    '92 K75RT, '02 F650GS Dakar;
    But fondly miss.. R80RT, R45,CB250RS,DT125MX,TS100

  2. #2
    Registered User WalterK75's Avatar
    Join Date
    Feb 2009
    Location
    Mississauga, Ontario
    Posts
    558
    This apparently is a chronic problem with these bikes. Search MOA there are lots of postings on this problem. I pulled the cable coupling (I call it that) apart on the right side of the bike behind the battery cover and used dielectric grease on the pins. This seems to have helped. Most often people think it is the odometer itself and it well could be. I tried this fix because when I pulled the plug apart and put it back, the speedometer seemed to work for a while and then fail. I attributed it to a loose connection in the socket there.
    Walter

    All government, of course, is against liberty.
    H. L. Mencken

  3. #3
    Registered User
    Join Date
    Apr 2012
    Location
    Los Angeles, CA
    Posts
    333
    The other offender is the connector between the cluster and the bike's wiring harness. (Note there's a similar tachometer problem just posted today as well.)

    Remove plug, clean connectors, apply Stabilant 22 or Deoxit (both are electrical connection enhancers).

  4. #4
    Registered User scoobs's Avatar
    Join Date
    Jun 2008
    Location
    Columbus,GA
    Posts
    250

    Question rear drive??

    I checked and cleaned all the connectors, but the problem still persists. Once again while on a test run I noticed that the Speedometer dropped off around the 40 mph mark and picked up again when I slackened off my speed to around 35 mph. Could there be something slipping in the rear drive? I presume the sensor is being triggered by a driven fine-toothed wheel to give the required impulses- could this be slipping??
    any thoughts welcome....
    Cheers,
    Ian
    Ian Robert "Scoobs" Scobie

    '92 K75RT, '02 F650GS Dakar;
    But fondly miss.. R80RT, R45,CB250RS,DT125MX,TS100

  5. #5
    3 Red Bricks
    Join Date
    Jan 2007
    Location
    Pleasanton, Ca.
    Posts
    3,392
    When mine started to get flakey, it turned out that the wire just before the connector on the speed sensor was broken and making intermittent contact.

    An easy way to check for this is to remove the speed sensor from the final drive and have an assistant hold a soldering or wood burning iron or gun about 1/8-1/4" away from the tip of the sensor. DO NOT TOUCH THE SENSOR WITH THE IRON. The 60 cycles from the AC current in close proximity to the sensor will cause the speedometer to read a constant speed (I don't remember what that speed is,but it's not important). Now you can start wiggling wires. When the speedo needle dips, that's your bad connection or wire.



    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  6. #6
    Registered User scoobs's Avatar
    Join Date
    Jun 2008
    Location
    Columbus,GA
    Posts
    250
    Thanks Lee, I've given the wiring a thorough check over and it seems to be intact- don't have anyone available to assist right now so can't perform the sensor check. I'm puzzled that the problem occurs at a specific speed, read a post on another forum about the "timing disc" inside the final drive coming loose and having to be refitted. It sounds a bit unlikely but perhaps it could build up enough inertia at a specific speed to lose traction, then regain it when the bike slows down ??
    Maybe problems in the final drive are also contributing to my ongoing (epic saga??) fuel consumption issues; although the bike runs smoothly and there's no obvious noise or overheating.
    Thank goodness I've got another bike to ride while I'm fighting all these gremlins- a non-riding friend suggested I just buy a new bike!! I wasn't able to convey my love for the K bike as an engineering masterpiece in a manner that made her understand.
    Thanks for your valued advice, I'll keep you updated as to my progress.
    Ian
    Ian Robert "Scoobs" Scobie

    '92 K75RT, '02 F650GS Dakar;
    But fondly miss.. R80RT, R45,CB250RS,DT125MX,TS100

  7. #7
    Route 66 Missouri gstom's Avatar
    Join Date
    Mar 2003
    Location
    Joplin, Missouri
    Posts
    695
    My 1988 K100LT odometer was flakey, so before I tried an IBA certified ride I installed a $30 bicycle computer as a more accurate odometer. This was a while back. I don't know if the IBA currently accepts a GPS track as evidence of the ride completed. Bummer that you had to cancel your ride as I am sure you were psyched for it.

  8. #8
    Kbiker BCKRider's Avatar
    Join Date
    Jan 2009
    Location
    B.C. Canada
    Posts
    761
    A couple years ago I had a flakey speedometer/odometer problem with my 1992 K100RS. The piece of advice I got from this forum which worked was " pull out each fuse and reinsert it a couple times."

    I know, this sounds just stupid, but as one who is definitely not "mechanically inclined" it at least fit my skill level. The fix (whatever it was) solved the problem and it has remained solved. Worth a try at least.
    Doug
    1992 K100RS

  9. #9
    A bozo on the bus deilenberger's Avatar
    Join Date
    Mar 2003
    Location
    Spring Lake NJ, USA
    Posts
    7,735
    You may want to go to: http://www.ibmwr.org/ - and look under "K-tech" (a wonderful resource for owners of older K's..) There are several detailed descriptions of reworking the problematical MotoMeter instrument cluster. Most likely one of the flat cable connections inside is coming loose.

    BTW - the number of articles on the instrument cluster are indicative of how reliable they weren't (or were if you consider sure to fail as "reliably failing.")
    Don Eilenberger http://www.eilenberger.net
    Spring Lk Heights NJ NJ Shore BMW Riders New Sweden BMW Riders
    '07 R1200R (current ride) and some bimmers.. and a Porsche

  10. #10
    Registered User
    Join Date
    Apr 2012
    Location
    Los Angeles, CA
    Posts
    333
    Quote Originally Posted by GSTOM View Post
    My 1988 K100LT odometer was flakey, so before I tried an IBA certified ride I installed a $30 bicycle computer as a more accurate odometer. This was a while back. I don't know if the IBA currently accepts a GPS track as evidence of the ride completed. Bummer that you had to cancel your ride as I am sure you were psyched for it.
    My read of the IBA rules is that they don't really trust your odometer to begin with. Hence the need for time-stamped receipts at start and end, and (not necessarily time-stamped) receipts documenting your presence at known points along the way. Odometer readings are listed on your log, but they note they'll likely change your total miles ridden to their own estimation based on your receipts. So it seems to me the bicycle odometer would be fine; what they want is documentation of where you actually were, not your record of where your odometer thinks you were.

  11. #11
    Registered User scoobs's Avatar
    Join Date
    Jun 2008
    Location
    Columbus,GA
    Posts
    250

    Thumbs up Fixed- I hope.....

    After much farting around I dismantled the instrument cluster and polished up all the connections with super fine emery cloth and gave everything a good spray down with contact cleaner. I think it was the 3 long pin connectors at the end of a pcb ribbon cable on the upper right hand side that were to blame, but I'm thankfull it's all back together again and functioning properly.
    Oh the joys of owning an older model bike
    Thanks to all who provided help and advice,
    Cheers,
    Ian
    Ian Robert "Scoobs" Scobie

    '92 K75RT, '02 F650GS Dakar;
    But fondly miss.. R80RT, R45,CB250RS,DT125MX,TS100

  12. #12
    Mars needs women! 35634's Avatar
    Join Date
    Apr 2008
    Location
    SW Ohio
    Posts
    2,037
    Quote Originally Posted by scoobs View Post
    Oh the joys of owning an older model bike

    Ian
    +1

    when I did that on mine it was still cutting edge modern!
    1987 K75S
    Original litter
    Original owner
    2012 Ural Gear Up

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •