Was a little worried that the thermostat wasn’t operating as it should since the temperature gauge hardly moved. Only on really slow riding it jumped up.
Tried removing the sensor but that didn’t want to come undone easy but for now its enough that the mechanical part of the cooling works. If the gauge shows a low reading wont matter as much. The sensor is also located in the thermostat housing. If we would have been able to remove that it can be boiled also and if you can measure the water temperature there is information in the workshop manual about what ohm it should have at different temperatures.
So sucked up the coolant from the expansion tank using a syringe and a piece of hose, since on the XL600V model its hard to remove to drain:
Started it up, just added a funnel to the fuel hose, a piece of steel wire to hold the funnel upright and a little fuel in it so we could run it a little gave it a little throttle 4-5000 rpm a few times to push any air out of the system, filled up and closed it let it run for a few more minutes trying to measure the sensor a little and the resistance goes down but since we couldn’t really know what temperature the water got up to we can’t be sure if the sensor is accurate, any problem could also be in the wiring or the gauge itself.
Drained it once more and added new coolant mixed with distiled water this time.
Later when we have more time we might look this over better but for now we are satisfied that all the mechanical stuff seems to do what they are supposed to.