Stock,
The higher pressure just makes the boiling point of the coolant higher so the rad won't overflow as often. It prevents loss of coolant but doesn't make the engine temp lower (unless without it you end up with no coolant). What you are describing doesn't sound right to me, but I am going from K5 memory (they are fond ones...). It sounds like you have air in your system which you will have to purge out using the purge bolt on top of the head (I bet you wondered what that was for). Normally when you fire up your bike with the cap off the coolant will stay at the level of the neck, with lots of turbulence, and sometimes spill over a bit. I would suggest you to run your bike and add coolant when the level drop to fill it up, then open the purge bolt until coolant comes out. Top everything up and you should be fine. Hope this helps. Cam.
