86 K 75 Speedo Problem

[will_kc]

My 86 K75 speedometer stops working after 5-10 miles of travel.  I have cleaned the rear sensor which was just lightly covered in oil.  Cleaned and greased the two pin clip behind the side panel and removed and cleaned the three pins on the speedometer.  I have had the cluster off the bike about three times now cleaning the pins (including a slight bend) with no improvements. 

Any ideas on other tests to run on the bike, cleaning of connections, etc.

Thanks,
Will

[franck]

Will
I have a 85 K75 and I have been to hell and back with the speedo.  It sounds to me like you may have to open up the cluster and clean contacts.  If the odometer ticks over the sensor should be ok.   I seem to remember someone telling me the later models had gor tex to limit humidity getting into the works.  There are some very good posts on stripping the cluster.  The circuit board for the speedo is connected by a set of pins – these may have corroded or worked loose. After cleaning connections I use SGB contact lube - expensive but one tube should last many years.  You can bench test the speedo using your computer and software KARAMBA  - again search the site there are some good info.
All this said - It has rained for several days and today I went for my trip to the village and the speedo stopped working ……  the time I got home it was working again – my guess  bad connections to the cluster or within the cluster.  If you strip the cluster advance with extreme care!!!
Best of luck
Frank

[will_kc]

Thanks for the link Franck.
I am waiting to get my K100 account approved now so can't download Karamba yet.

My multimeter shows a pulse from the sensor to the instrument cluster connector (pin 22/23).  The pulse passes through the first circuit board (4 lower pins on speedo) and is converted to a variable voltage for the second circuit board (3 pins on speedo).  I can see the voltage change as the bike accelerates but the speedo is unresponsive.

Have any others reading this worked with testing the moto meter circuit cards?  I don't know what to test for on the card behind the speedo gears.  It is feeding a transformer.  I did adjust and clean the connectors while I had the speedo apart, but that did not help.

Thanks,
Will

[kennybobby]

i had this problem some years ago, and discovered that the two boards inside the IC were connected with a sliding contact terminal--a male pin and a female clip.  The clips had worn (vibration on the road) and expanded such that the connection was intermittent.

i ended up soldering the connections to avoid the sliding contacts, which to me are a total abomination in electrical and electronic circuits.  Solder can easily be removed with copper wick if the unit must be opened again some time, but so far no need.

[franck]

Will,
May be its too late and the found the Karmba info - if not you can down load it direct from this link
http://hrsbstaff.ednet.ns.ca/bvogel/karamba.htm
The site also gives a good guide on how to use the software.
Another link that may be helpful
http://www.ibmwr.org/ktech/speedo-repair3.shtml

Frank
ps my speedo came back to life - dry weather and a quick clip around the ear and it works fine (for the moment)

[will_kc]

Franck and KennyB,

Thanks for the links and Info.

The sliding contacts did seem to be an "Engineering brain fart" when putting the speedo back together.  I have Karamba now so it should be much easier to test the unit while disassembled.  It's never to late, but there is a Ram mount for my GPS on the handle bars now.  Getting ticketed for being over the limit is getting rather expensive in this part of the country.

Will

[Brahma]

I just posted this last night, and road tested it today and it solved my problems;

http://www.motobrick.com/index.php/topic,8644.0.html