Motorrad = very bad.
You need a 180 degree t-stat. The gray one from Landrover.
If you have air in the system - you will over heat.

to test - take the radiator cap off carefully.
Take the engine speed to 1,300 or so RPM for about 5 minutes.
if the truck pukes out water - your head gaskets may be bad.

It the truck does not puke - then raise the coolant tank by unclipping it.

Keep the tank raised.
Run the engine at 1,500 for about 10 minutes.
Keep putting coolant into the tank.

That gets all the bubbles out.
Using the supposedly "right way" of bleeder valve never worked for me.

If you can run the engine at 8 to 10 minutes with the coolant tank raised up
and it does not puke out water and you get all the air out - you'll be fine.

Except for the motorad thermostat.

That that Motorad thermostat out an smash it with a hammer so it never works again.
That way no one will be tempted to use it over again.
Throw it in the ash can.

Sort of like a bad computer network cable. Cut the cable in half and throw it out.