I have a KZ 1000 shaft drive with 53000 on it and it runs better than ever.I can´t understand the over reving you have,It might but the extra miles on yours.I have had two new bikes and a used honda since having the 1000 and i end up riding it more; a lot more.Gusse you could say i´ve bonded with it.I did replace the seat at about 50,000.I lucked out and found a new origional seat for $125, worth every penney.Have fun riding. Kaw-man "Rick"