Just put in a new water pump seal, after searching through the threads on this procedure. The info there was very helpful. The impellar does unthread like a typical nut, my local dealer didn't know. I really didn't want to pull off the entire right crankcase cover, but I was concerned about snapping off something internal. But elected to give it a try. I put the bike in second gear to lock up the shaft, used a heat gun to heat up the impellor where it attached the shaft and used my impact tool working it CW the CCW and it did come off, although it resisted. There was some residue on the bearing behind the seal so I flushed it with some WD40, if antifreeze can leak out then dirt can get in. I have a needle fitting that fits into my grease gun so packed the bearing with grease. I tried seating the seal with a spark plug socket, but a socket reversed works better as the shaft will fit through a 3/8 square ratchet hole. If you do this yourself you have to pull the exhaust header to access one bolt holding the pump cover on and this is a little easier if you pull the right side radiator as well. Thanks for the help.