Alot of people rip on Kawis claiming that they are horrible for reliability. Well I keep up on regular maintence on mine, jetted it right, and I have never had a horrible failure on me. The worse thing that happened is that the linkage bearings seized up but repacking them full of nice quality grease after working the crud out of them did the trick! It also fouled spark plugs now and then, I got the hell off the Klotz BeNol and jetted according to PC specs and it hasnt missed a beat since!
Ive seen all kinds of other bikes, even newer ones then mine, which are poorly maintained and they break alot and run like garbage. Dirt bikes are subjected to some of the worse conditions imaginable for mechanical things and they need to be maintenced regularly! I dont care if its a Kawasaki or a KTM or whatever, you abuse them, you dont service them, they are gonna feel like junk real quick!
So if its near mint and you keep it near mint yourself, chances are you will have a nice reliable bike.
Oh and 2500 for a 97 seems a bit high, even a mint one. I assume you are talking in dollars.