the bottle is not mandatory to keep your radiator full to the top. i cant remember the last time i put collant in mine, and its still full clear to the top, with no coolant bottle. if you run the overflow to the ground, itll never over flow on your pipes anyway. i even took the one off my 450 which got rode hard as fuck everyday, for many hours and i never had to refill the radiator. those bottles are pointless.