ok heres how it goes...
The process is the same way as a car, for the most part, except you dont need the vaccum machine.
Drain all of the coolant by removing the hoses from the engine. The bottom ones that is. this should drain the coolant from the radiators and the engine. Next, fill the radiators up with 50/50 water/antifreeze. Fill the over flow to the full line. Put the caps back on and attatch the hoses. Next run the bike. Once it is warm, take off the radiator cap. Add fluid if needed.