Well my GS750EF is for sale but I'm in Canada and it's also in very good condition, YOu probably wouldn't want to wreck it. My friend and I tore down the engine at 76 thousand K as a winter project and replaced the valve springs and seals, reground the valves and checked the rings and cylinders and cleaned up the head and pistons. Even after 76K and God knows what kind of servicing all the rings were in excellent shape. The cylinders were all good too, except number 2 was slightly more worn but well within spec. Slapped her back together and she drives like a new bike. It just shows how bulletproof these bikes are. Mine has been re-jetted and had a Yosh pipe on it when I bought and its pretty peppy(85 horespower stock, 90? with Yosh and jet). Coming from the 80's it has pretty good ergos too. very much like the bandit but with drop bars. Here's a pic of the model I have:
Full fairing version and same colours:
In fact I think the KAT engine is a variation on the same engine as mine. I looked at a KAT750 engine and is was identical right down to the oil cooler and oil lines. This may be cosmetic only I'm sure they tweaked the cams for more mid-range or whatever. These engines are super reliable and very hard to kill. Look on e-bay or at a wreckers for a complete engine.