Where on the engine block would I put a thermometer for a quadbike?

I have a Honda 350D and the fan thermostat has broken, rather than spending money replacing the unit I'm looking to wire the fan into a switch.

I have also purchased a digital thermometer which I plan to wire in, but I need to place the receiver on the engine block, but which part do I connect it to, top end, or radiator and if so top of the radiator or bottom? (oil cooled).

On the output side of the radiator, but that's just a guess.

You can't afford to replace the thermostatic switch yet you have bought a digital thermometer? Doesn't make a lot of sense to me.

Online that part is $20-$30. You are going to risk overheating your engine for $30? Just wire it in so the fan is running whenever the ignition is on if you can't afford $30, at least then it won't overheat.

A PROPER repair will cost LESS than your plan. Besides, running the fan ALL THE TIME will work better then your idea.