I just got an 03 WR450 and it is set up for supermoto. Do I really need to have that radiator bottle thats behind the left number plate. I know its an over flow bottle but why does it have level marks on it, like low and normal. I want to mount my tail light in the place that the bottle is in. I have a 06 YZ250F and it has no bottle. Why the WR's have them and YZ's don't.