try replacing the radiator cap. sounds to simple but worth it to check out. alot cheaper than replacing the water pump. if the cap wont tighten down the pressure inside your radiator isn't correct and will allow the fluid to boil over. or at least thats a very basic desscription of how it works. but as I said before it's def cheaper than replacing the water pump! Good luck and keep us posted.

 

f4s have a fan problem sometimes the rim around the fan hits the fan making it short out the fuse and the bike overheats