I am also in the process of rebuilding my carbs off a 1981 KZ550C LTD. Like yours, mine didn't run and had been sitting in a garage for about 12 years. The first thing I did was find a complete manual in PDF form online and put it on a flash drive, took it to Staples, and had them print me up a bound book for about $43. Totally worth it btw. The manual is actually a really good one. Very well written and informative. It tells you how to completely disassemble the carbs with pics. Secondly, you can rebuild the carbs with jets and all WITHOUT breaking down the carb bank into singles. Just make sure you have plenty of space on your bench to keep everything in order. Each carb with its own parts. Take pictures throughout the teardown. Ive had the carbs out and cleaned several times but not happy with the results so rebuilding now. I replaced the airbox boots and it made a huge difference in getting the carbs in and out. Last night I had the carb bank out and disassembled with jets out in about 1.5 hours, taking my time. All the brass parts can be soaked in chem-dip. I've been using carb cleaner for the rest. I cleaned the pilots with a guitar string, but now replacing them anyway. The first time I did a thorough carb cleaning it went from running only on choke to being rideable without the choke and accelerated better, but would plateau at 5500 RPM. I found out this was due to the timing advancer being rusted into a fixed position. As this time, the bike can still only get to about 75 MPH. That's why I am looking at rebuilding the carbs, then resyncing them. This was also my first bike rebuild. Here is the link to the manual.
www.nwsca.com/gpz550/KZ550%20Base%20Manual.pdf
I have a question for anyone reading this....the air screws that came in my rebuild kits are longer than the factory ones, is this a problem? See pic.
Good luck