When it's cold (to avoid covering yourself with boiling water) take the radiator cap off and start the bike, rev it and you'll see the water rushing about and likely the level will drop a bit when revved. This shows your pump is fine, if the pump wasn't working it wouldn't take many minutes long to boil up. Put a meter on the terminals of the fan switch and run it to see if it switches when hot enough, problem being that the fan won't come on while you are going this, best to put a test light between the output of the switch while still connected and the battery and see if it comes on at all. Sounds like the head gasket could be stuffed, this could show by making the hoses hard by pressurising the system when running and would likely make water exit the radiator filler swiftly when the cap is off while running. Boiling up a bike is a swift way to a screwed head gasket so if it's not this, you need to sort it before it is.