I did get the second little Kawasaki running. Not great but good enough to warrant proceeding with a carb refresh and making a few other repairs like brake master cylinder and caliper rebuilds. Then, while waiting for the carb kits to come in, I though I’d pull the rear wheel to check and clean the rear brakes. And it was while spinning the wheel I first heard the “clunk”.
It was coming from the front sprocket, so I pulled the cover off and, sure enough, at one point in the rotation the drive sprocket drops a couple of millimeters. This is NOT good.
I might as well forget about carbs for now; the entire engine needs to come out. Fortunately I have engine no. 3 in the shed so I guess I’ll be doing a swap in the near future.