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K75 Speedometer not working Tue May 09, 2023 9:52 pm
jjefferies
Life time member
My Red 1991 K75 had been sitting for a spell while I've been using the Silver K75. No particular reason but today I thought to take Red out for a ride. First thing I noticed was that the speedometer was not working nor was the odometer. Tach and all the other instruments were working correctly. My initial assumption/guess was that corrosion was interfering with the signal from the rear wheel pickup. And if the speedometer wasn't working then the odometer would not either. This must have occurred while Red was sitting in the garage out of the weather as I don't remember any such issues when I last put Red away.
Returning home I took the instrument pod off the bike and using a electrical cleaner sprayed and cleaned the connectors and the pins from the instrument pod. Reconnecting the instrument pod to the connectors I started the bike and with it on the center stand ran it through the gears, i.e. I mean that I had the rear wheel racing quite fast. Still no movement from the speedometer. So I checked the rear wheel pickup. Not much to see or check but I pulled it and cleaned it and re-inserted it. No change in the symptoms. I have another instrument cluster from the current project an '86 K100 and so substituted it for the K75 instrument pod. Symptoms remained the same. Other instrument lights, tachometer etc work but not the speedo. Now the K100 may or may not be totally functional and a complete swap for the K75. Though I would have thought they (K100, K75) are the same. I did note that the K100 instrument pod gear indicator not working.
My reading of the Haynes and Clymer manuals electrical schematics indicate to me that the circuit between rear pickup and speedometer are rather simple, two wires. But
1. Has anyone else run into this problem? Your findings?
2. Any pointers to how to discern which pin is which on the two instrument pod connectors? I would like to ring out the circuitry for shorts and check resistance of the pickup.
3. Suggestions of things to look at or try?
thanks and best regards
J.Jefferies
Returning home I took the instrument pod off the bike and using a electrical cleaner sprayed and cleaned the connectors and the pins from the instrument pod. Reconnecting the instrument pod to the connectors I started the bike and with it on the center stand ran it through the gears, i.e. I mean that I had the rear wheel racing quite fast. Still no movement from the speedometer. So I checked the rear wheel pickup. Not much to see or check but I pulled it and cleaned it and re-inserted it. No change in the symptoms. I have another instrument cluster from the current project an '86 K100 and so substituted it for the K75 instrument pod. Symptoms remained the same. Other instrument lights, tachometer etc work but not the speedo. Now the K100 may or may not be totally functional and a complete swap for the K75. Though I would have thought they (K100, K75) are the same. I did note that the K100 instrument pod gear indicator not working.
My reading of the Haynes and Clymer manuals electrical schematics indicate to me that the circuit between rear pickup and speedometer are rather simple, two wires. But
1. Has anyone else run into this problem? Your findings?
2. Any pointers to how to discern which pin is which on the two instrument pod connectors? I would like to ring out the circuitry for shorts and check resistance of the pickup.
3. Suggestions of things to look at or try?
thanks and best regards
J.Jefferies
