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Water temperature gauge

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    • Water temperature gauge

      Hi Guys,
      Anyone got any suggestions? I've just put together a 1991 K100RS4v (VIN 0201103), it all runs but as soon as I turn on the ignition, the water temperature gauge goes right over to the end stop at the 'hot' end of the scale - and that's before the engine has been run! I got to the temperature sender unit behind the radiator and disconnected it but the gauge still went hard over. Is there only the one temperature sender on my bike or is there a second one? If so, where is it? I've seen a US web site which suggests that there is a second sender just for the gauge but I can't find it if there is :question:
    • Re: Water temperature gauge


      "Solong" wrote:

      as soon as I turn on the ignition, the water temperature gauge goes right over to the end stop at the 'hot' end of the scale

      Are you sure the connections to the gauge (i.e. on the instrument itself) are correct? To me this looks as if a wire is in the wrong place ... :geek:
      Gruss aus der Westschweiz,
      - Joerg

      Meine Motorradseiten | Unser | 1990er K100LT und R80GS
    • Re: Water temperature gauge


      Silly thing, but maybe wires are swapped at oil switch and temperature sensor on water/fuel pump :idea:

      These sensors are quite near and connectors are similar. How does oil pressure light work? Does temperature needle fall immediately after engine start?

      • oilpump.jpg

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    • Re: Water temperature gauge

      Blowed if I can see the second sensor - I can find the one behind the radiator but there appears to be a blanking plug in the water pump - I must be looking in the wrong place! However, the 'lack of earth' idea prompted some serious cleaning of contacts and, viola, i now have a working gauge. Looks as though earths could be fun on this old girl!
      Thanks guys, that's another problem solved - back to brake bleeding - "bleedin' brakes!"
    • Re: Water temperature gauge

      "ReneZ" wrote:

      I'm not aware of any K type bike that doesn't take its signal from a sensor in the waterpump, unless someone fitted something themselves.

      The coolant temperature sensor on my two K-100's, also called the NTC-2 sensor for Negative Temperature Coefficient is located on a manifold on top of the block on the left side immediately behind the radiator. That is the one and only coolant temperature sensor on these two bikes. The sensor on the oil/water pump is the oil pressure sensor. I have not seen a second sensor on any oil/water pump yet.
    • Re: Water temperature gauge

      Thanks Rene, found it (at last!) - nicely hidden. It will be replaced.
      Thanks to all you guys who replied - it seems these bikes changed a great deal between models and years, nice to know my RS4v is such an odd-ball machine!