I can't help you mate, I did have a spare sender, but it snapped in the housing while I was trying to remove it......
Good luck tomorrow trouble shooting, I look forward to hearing your results.

Any luck with this then?

An update for those who are keen.

I managed to get the fuel tank out today to troubleshoot with the thermo units. The mechanical thermostat valve appeared normal. The thermos sender unit that sends the electrical information to the gauge appeared normal as well.

I next tested the connections with a Japanese instruments panel (broken into bits and pieces) and the temperature gauge needle moved (Good sign).

I next tested the connections with two different Chinese instrument panels. Both times, the temperature gauge did not response at all to the ignition being switched on.

Conclusion, the Chinese panels temperature gauge are probably of poorer quality. The short term solution is to perform an immediate transplant, which I am fairly confident of doing. The long term solution is to continue to troubleshoot to figure out why the Chinese clocks don't work. (Resistance? Wiring?)

So you're saying that the Chinese gauge won't move at all?

You confirmed that the Chinese gauge had 12 volt power supplied to it, right up to the wire connector on the temperature gauge itself (not just a main, general instrument cluster connection)? Then you "jumpered" (directly to the bike's battery negative pole) the gauge's wire connector that normally goes to the temperature sensor?

And nothing happened? That's surprising.

From reading posts about these Chinese instrument clusters I see that the Tach and Speedo seem to work just fine, which says that the people making the instrument cluster can do the job, but the temperature gauge part doesn't work. I don't think the Chinese constructor of the cluster would let it leave their factory without it first passing an operational/functions test. So I'd have to guess that there's simply a mismatch between the input-output conditions the Chinese manufacturer is using to calibrate/test the cluster and the input-output conditions the gauge is getting when installed on the bike. Maybe the Chinese constructor uses this same gauge in replacement instrument clusters for multiple types of bikes.