Hi Spen, no special method is required, to up the radiator while the bike is on the sidestand and also check the expansion tank is at the upper mark

the expansion tank should take care of any air trapped as it takes the excess coolant when the system heats up and when the system cools down it draws in coolant through the valve in the pressure cap to 'top up' the cooling system.

whats the story your bike draining the tank? mine never needs topping up since i replaced my busted radiator

bernard