Old Kawasaki fours are great engines, i've owned a Z650, Z750 and Z900 and these engines are pretty much bullet-proof, moreso than our sohc-4 engines. Kawasaki couldn't make their bikes handle until the mid eighties though, so don't expect too much in that department, although the Z650 was actually quite a good handler compared to the Z900/1000, Z1R, and early GPZ1100's.
Be very careful around the fuel injected models though, they're trouble with a capital "T". Best thing you can do with these is swap the head for a carburetted model, but that's a pretty big job. Also, if it's been parked outside for that long you'll need to assess whether it's worth piling money into, more than likely all the cosmetic items will be beyond salvage, and the engine could well be seized. Kawasaki parts prices make Honda restorations look cheap, I gave up on them when i restored a Z750L1, it cost me more than the original purchase price, just to do a "cosmetic" restoration. Cheers, Terry.
