should be a piece off piss mate just a case of emptying radiator unbolting waterpump pulling off old O ring pushing on new.. edit looking at my blackbird manual you have to align the slot in the waterpump shaft with a tab on the oilpump shaft when you push the water pump back in whether thats the case on a 600 i dont know but you should see when you pull take off your water pump.
yeah just seen that online water pump is powered off clutch wich in turn powers oil pump and needs to be lined up correctly
Eddie it's dead easy but wait don't undo all the bolts just the the 2 that mount it to the engine really easy to slot back in line up push in it will push straight back in lined up properly
http://parts.hondaofbournemouth.co.uk/products/2001-158/water-pump-cbr600f-4821.aspx - Have used them for some parts on my Varadero, they were reasonable. I started to use ESB Motorcycles in Leigh for small parts, due to the shipping cost online.
