...caveats I'd add...are (1) that a few models appear to be not available on the Kawasaki site. For example, you ultimately get an error message when searching for Z1A and Z1B models. On the model line, you must insert a '-' between the Z1 and A or the Z1 and B. The model name will initially look like this: 'Z1B' and you should change it to look like this: 'Z1-B'. Click the green arrow to the right and then you will get the exploded diagrams....
I did a similar post on a dirtbike forum which helps out bigtime since dirt riders are constantly swapping parts.
One thing I would like to add:
Alot, not all, Kawasaki parts have the last 4 digits of the part number on the actual part. These last four digits is what seperates a particular part from another in regards to the "Reference Number". Basically, a reference number ONLY references the part in the diagram and there may be 100 different parts with the same reference number but different last 4 digits of the part number.
A cylinder for a 2 stroke engine reference number is 11005. so that's the first part of the part number. Kawasaki pretty much changed porting on their cylinders annually and each one got a new part number. One of my cylinders has "1851" stamped on the side. So I take the reference number and add the last 4: 11005-1851 and I can tell now I have a 1998 KX250 cylinder. There may be 20 cylinders that look the same but those 4 digits is what defines them. If you look around your bike you'll start to see all the part numbers.
One of the colossal benefits to looking up parts on Mother Kawasaki's site was that you could determine if a part was still available from a Kawasaki dealership (or in my case, Z1Enterprises). As it turns out, I was looking for a rear signal bracket for a KZ1100-B2 and the Kawasaki site showed the part as still available (still does BTW) ...steep, but still available. Great! Ordered it from Jeff and was told shortly later that the part was NLA. So, just because it is noted as 'active' on Kawasaki...it isn't necessarily so. Alas.
As I stated in the other post, I actually work on the Kawasaki Website. I can't speak for Kawasaki, but it's my belief that we are doing everything in our power to provide all the parts diagrams for pre 1984 products as they were on the previous site.
As an owner of a 1977 KZ1000, I totally understand your concerns. Please be patient as this new site was a major undertaking. I can assure you that Kawasaki Corporate has received many complaints about the missing parts diagrams.
I'm not telling you to quit asking, just asking the community to be patient. Thank you for being loyal Kawasaki customers.