I have very fond memories of my FZR400, FZR600, and then even moreseo my FZ750...
They are fun bikes, but if abused and the valve adjustments not done can get trashed pretty easily. Charging issues aren't very common so that would have me nervous...the alternator is just a bolt on ordeal that runs off of a splined shaft. Hopefully the splines aren't stripped if he already tried to muck with it. Good news is you should be able to find one on ebay...check and see what other FZR bikes might have the same alternator...probably the FZR1000 even...it should just be three bolts and make sure you get new rubber o-ring seals for the splined shaft and you might be good to go. Make sure the electric start works ok too, the plastic stupid gears in the engine case that the starter spins tend to break on bikes that have been abused...neglected.
Fun bikes, fairly easy to work on, dead reliable if well maintained (that part in question for this one lol). The problem I have is that isn't a very good price for a bike that has been hacked up, has a salvage title, and has who knows what kind of history. I'm sure if you are patient you could find a much better bike for just a little more money...hell I got my last FZ750 for 1200 bucks and it needed nothing other than minor maintenence.
