[Rorty]

I always run some form of additive whether it's achohol based or contains some type of surfactant. They reduce the liklihood of air bubbles and cavitation. Cavitation is a real problem at the high RPM these bike engines reach; granted the engines are much smoother die castings than the rough sand-cast car engine blocks, but even so, it's always wise to include a coolant additive.

If the coolant spews, it would be wiser to address the overheating problem than exacerbate it by ommitting the coolant additive!