Over heating

Interesting. Run the bike with the coolant over flow bottle empty. Not on my bike. if you take the bear claw off, check the radiator cold and it's full and then with the bike level fill the coolant over flow bottle to the cold position, it should not puke out any coolant. if it does, one would want to check the radiator cap and then the thermostat. At least conventional wisdom would take you on that path.
 
I always just overfill them and let it equalize itself. If they don't belch all over the ground after reaching operating temp I fill it again. You can never get all the air out the system manually without spending time doing it, letting the system cycle and making a mess is a sure way to get it done the easy way.

You have to think of it like the mercury in a thermometer, if it has a bubble in it just run it through hot and cold cycles until it goes away. The reservoir is just a place for the overflow to collect until it cools and gets sucked back in.