Ok I just picked up an 06 WR 450. Put a JD jet kit in all the free mods changed the oil. I want to flush the cooling system and refill it with fresh coolant. What is the cotton stuff in the overflow line? Can I use the automotive all makes all models antifreeze or should I use the yamaha stuff? I got an awesome deal on this bike only thing left on the to do list is valve adjust and maybe change the cam chain. Thanks in advance for the help.