Cheap,waterproof,accurate and easy to install,hope it lasts under the Greek sun. Top Gauge Digital Motorcycle MotoBike Oil temp Gauge Meter RED LED Waterproof | eBay
A local machine shop made for me a T adapter for about 20$ to connect the temp sensor on the 20mm coolant hose above the thermostat at the left side of the engine.I haven't found something cheap similiar to that on ebay.
I finally arranged sensor,cable and hose clamps so they cleared radiator and fuel tank.
The best place to fasten the display was under the handlebars.Εasy for me to watch it but not for the vandals.
In front of the tachometer you can see a big horn from Hella,i ride my berg on the streets.
Behind the front mask,connect red(+) termignal from the gauge on this yellow wire(not yellow-red,just yellow) that goes to the front brake switch.
It is a 12volt AC supply,NOT DC but it is okay,the display likes it.For safety reasons you can use something similar to this electronic device: AC-DC Converter 6/12/24V to 12V Full-bridge Rectifier Filter Power Supply Module http://www.ebay.com/itm/232175110391...%3AMEBIDX%3AIT
So now your gauge works only when the engine runs,there is no need for an extra switch.
The negative termignal from the gauge goes to any brown wire(-) you find behind the mask,one from the turn signals is preferred.