I have to drain the coolant and replace it with water for some upcoming track days. Just thought I'd ask if anyone has any tips or bad experience with running just water. I was going run water until the end of the summer. Thoughts?

 

I would recommend running water + Water Wetter. It has better cooling properties than straight-water.

You'll definitely want to switch to antifreeze coolant for the cold temps.

 

If you run only water in a dirt bike it will seize the engine. I think the same thing would be true for a street bike. I'm no expert, but I beleive antifreeze also acts as anti-boil. They make special coolant specific for track use.

 

I would run engine ice personally

 

I think with straight water you are also risking corrosion.

 

Some trackday providers/organizers specify against EI because it has a glycol (I think...?) based additive that makes it as slippery as antifreeze.

 

I'm no expert but I believe you have to have some kind of lubricant/additive for water pump.