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How to troubleshoot my oil temp gauge/ground problem

Thanks M' one. Unfortunately, I do have an intermittent problem but this will be a good starting point.

Irratic guage, either the guage pointer/mechanical movement is sticking or the sender has a dirty/burnspot in the variable resistor rheostat inside.

1) To test the sender, open the wire between it and the guage...set your meter to "Ohms" and zero it on Rx1 scale 1st (I do not know how much resistance to ground it is so you may have to rescale if you do not see meter movement when testing after this califbration) with both test leads shorted together. Now attached the black to ground (base of the sender or engine/frame) and red to the connector insulated contact. Fasten down everything with electrical tape and secure the meter as you will want to start the bike and you should see the meter move smoothly from some value towards zero when raising the throttle "gently". If it jumps around, the sender is bad. Because you are troubleshooting an intermittant problem, you may want to reconnect guage and check if irratic operation is reflecting what you tested.

2) Testing the guage is harder because, you have voltage & current feeding it that has been scaled down by a "shunt" or dropping resistor and sometimes it will only take 1/100 of an amp to "kill" it, but you can use a DMM (it has isolated "display" electronics in series on the highest current scale first with it...DO NOT USE YOUR ANALOG METER...you may peg the pointer and burn out your precious relic...DMM's like one from Harbor Freight for $5 to $9 surprisingly are better at this, relax and enjoy your methodical troubleshooting!
 
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