Hi, I have the same problem with the ODO on my 1990 kdx. I imported the bike to Canada and in doing so I had to check for recalls on the vehicle by calling up Kawasaki USA. I found out that my 1990 model had a "Factory Directed" recall(not a mandatory recall) on the Odometer. This means that Kawi USA would pay for the repair (although I haven't gone to see if they would do it in Canada or not yet). I would check that first...I'm pretty sure this is the phone number I called: 949-770-0400. Just give them your VIN and they should be able to give you a yes or no. Just ask if there was a Factory Directed recall on the bike.
Good Luck...