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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: paratrooper34 on July 11, 2018, 07:44:19 PM

Title: New (to me) 1988 K75S
Post by: paratrooper34 on July 11, 2018, 07:44:19 PM

Greetings Everyone!

    I purchased this '88 K75S this past weekend.  I am the fourth owner and the bike has an undetermined amount of miles (estimated to be around 22K) due to a couple of speedo swaps.  One was documented with a sticker under the seat and the rest is word of mouth from previous owner.  Anyway, she is in pretty good shape and looks good from ten feet. 

    So, the speedo does not work, nor does the odometer.  It worked only for a little bit during a 20 mile ride this evening.  Previous owner told me it needed to be replaced.  I asked if it was the cable or sending unit, but he was certain it is the instrument.  My question is:  how can I be certain that it is the speedo that is bad?  Can it be fixed?  I want to use this bike to commute right now, so I really don't want to send it off for repair.  If it is not something I can repair myself, I guess I can find another to replace it.  If it needs to be replaced, anyone have they want to sell?

    Thanks in advance!

Title: Re: New (to me) 1988 K75S
Post by: rbm on July 11, 2018, 08:44:33 PM

Read this thread:  Karamba Speedometer Calibration Program (http://www.k100-forum.com/t2038-karamba-speedometer-calibration-program-tutorial)

Karamba became K-diag.  It's available here (https://drive.google.com/open?id=0B3UPbNZRyr1rVzByWk1mM25IeWc).

Title: Re: New (to me) 1988 K75S
Post by: Martin on July 11, 2018, 09:11:17 PM

Welcome to the asylum from the land of OZ.
Regards Martin.

Title: Re: New (to me) 1988 K75S
Post by: Barry in IN on July 11, 2018, 10:50:31 PM

Welcome!

Title: Re: New (to me) 1988 K75S
Post by: wally.fisher on July 11, 2018, 11:45:36 PM

Before you dive, look at the electrical connectors to the cluster and inside the cluster. Google is your friend.


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Title: Re: New (to me) 1988 K75S
Post by: stokester on July 14, 2018, 11:05:47 AM

Welcome to a fellow vet.

Before throwing any parts at this I would first check out RBM's great post regarding the cluster -> http://www.motobrick.com/index.php/topic,10566.msg90724.html#msg90724 (http://www.motobrick.com/index.php/topic,10566.msg90724.html#msg90724)

With both the speedo and odo failing at the same time I would suspect that it is not getting an input from the speed sensor.  Make sure it is plugged in (there is a plug on the RH side near the coolant reservoir) and that it is clean and secure.  Then check the connector at the cluster for corrosion or even a retracted terminal since it has been replaced a couple of times.  I don't know the frequency range of the sensor or if it can be checked at that RH side connector without an o-scope but RBM may be able to offer a suggestion.

Title: Re: New (to me) 1988 K75S
Post by: paratrooper34 on July 14, 2018, 08:15:39 PM

Thanks, I will check all of that.  Much appreciated.

Title: Re: New (to me) 1988 K75S
Post by: daveson on July 14, 2018, 10:07:08 PM

i fixed that problem on my bike
i found a youtube clip on k100 instrument cluster
in my case it was the three pins on the right side tethered to the left
i just sanded them and pushed them in and out say twenty times to remove the corrosion, after a while the problem came back
i cleaned them a second time but also bent them slightly for a more snug fit, i think this time it is fixed
but ive only had it registered barely one year
happy riding