In the US, for the KZ1300 we had both A (Naked) and B (Touring) models. The A and B models are similar and people have converted B's to A's. The main differences that I know of on the 'B' frames is they have a bracket on the head to hold the fairing and they don't have rear turn signal mounts. All of these models have carbs. None of these bikes had gauges on the tank. There are 3 different tanks though. Not sure if all 3 where available in the US. So 1979 had only As. 1980-81 had As and Bs.
I don't think the US had 1982 models. Or maybe those where the A4 models. I've never seen one in the US, but I'm not an expert...
The Voyagers are ZN1300 models (1983 on) and are quite different. Frames are completely different, many engine parts (including internals) are different. All of these models have FI.
Other parts of the world continued to get KZs when we got ZNs, so they have KZs with FI in the later years.
For me personally, the 1981 A3 model would be most desirable as it has all the improvements.
Actually the 1982 A4 model was in the US. It came with a 'peanut' shape tank. They are rare, I've been actually told this is the rarest of the models therefore rarely seen. I heard 'California' referred to them, and mine has the 'CA' in the VIN serial number (most available are A1 - A2). The A4 comes with all the latest whistles of the carbureted models, including two alternators and those discussed 20 holes pistons, the engine is very wide because of this (not the pistons lol). I've literally built mine from scratch including chrome plating all that you see (and some you don't). It was a messy wreck with most parts missing, but only 8k miles, so pretty much a new bike after putting all new in the top end, and every bearing, seal, brake system component, as well. The black is standard Kawasaki ivory black, but I put off adding the stripes for later - I like the modern twist to this bike with this black theme. Sorry for bragging but I put so much heart into it! And yes, I built in my living room!! haha
There are also 'naked' ZG models, and they are fuel injected. I think these were European.
1982 Kawasaki KZ1300 A4
Building an engine from random parts. This will eventually morph into building a bike from random parts - if it ever happens. Need a frame to begin with.