magg wrote:Why not follow neosophist's suggestion and check for a resistance change with temperature from the temp sensor first, then move onto the the thermostat.

indeed, even with a stuck thermostat some amount of coolant will flow past and the temp sensor will still regiser...

You might want to check your measurements.

If the wire from the sensor is shorted to chassis and also connected to the temp meter, then the meter would indicate full scale continually.

For the sensor wire to be shorted to chassis and the temp meter to indicate low scale, the sensor wire must also have a disconnect from the sensor somewhere. An open circuit and chassis short circuit in one wire is possible but unlikely.

magg wrote:You might want to check your measurements.

If the wire from the sensor is shorted to chassis and also connected to the temp meter, then the meter would indicate full scale continually.

For the sensor wire to be shorted to chassis and the temp meter to indicate low scale, the sensor wire must also have a disconnect from the sensor somewhere. An open circuit and chassis short circuit in one wire is possible but unlikely.

Good point, the wire obviously is connected to the gauge on the correct pin as it goes full when shorted to the frame.

My multi meter also beeps when touching the sender wire with one lead and anywhere (ground) on the bike with the other lead.

I will try have a look at the gauge tomorrow, make sure its all connected correctly and try see if there is any botch work going on (unless anyone has more ideas based on the readings)

Is the sensor wire connected to the temp gauge or the sensor when you connect the mutlimeter leads and get a beep sound? You need to isolate the sensor, the wire and the temp gauge from each other, otherwise the readings may be compromised.

How are you sealing the sensor? If using ptfe it won't be able to complete the circuit.

So this has been a while, but I bought a car and shelved the bike for a while. Been fixing it up a bit now again and seem to have this sorted. Not happy with how though....

So I stripped the tape off the wiring loom to check for any issues and it started working. There mus be a cracked cover or something which is leaking the signal or something.

Taped it all back up and seems to still be working fine. Probably need to replace the wiring or something soon.

For now I might have a working temp gauge for the first time in 4 years :D

balashark wrote:How are you sealing the sensor? If using ptfe it won't be able to complete the circuit.

That was a good call, its ptfe tape but should not make a difference. there is liquid in there touching the end of the sensor which is in contact with the rest of the engine. Multi Meter shows continuity between the sensor and earth also so all good there.