New to me '78 KZ200 (1166 og Miles)

Hello all! Thank you for accepting me to the forum. I just acquired a 1978 KZ200 with 1166 original miles on it. It was last tagged in '82 and has sat since then. The bike is physically in great shape, although it did not come with a key so I bought it without being able to look into the tank. It is basically made of rust on the inside and probably cannot be saved. In addition, the engine appears to be seized. It has been soaking with Marvel Oil for about half a day now and I believe I will try to turn the crank by hand in a few days.

I am in search of advice about how to get the engine unseized, and if/when I do what else will need done before I continue trying to get it started (rebuild eng?). I've got a carb rebuild kit on its way as well, in hopes that the engine does in fact free up.

Thanks

Welcome! I have been trying to add a Kawasaki single to my small collection for years, ever since i saw a cafe version at a VJMC event years ago.
You are doing the right thing by easing into turning the engine over. As for carb kits, I generally avoid them since the jets are usually junk and all you should really need is a gasket, or O ring after a thorough cleaning. For the key, get the number off the lock. A member here can probably set you up with one.  
Don't forget to add pics. 

Welcome.
Post up some pictures of your find.
I can make a key by the key code number.
Let me know if I can help.
New original ones can sometimes be found on ebay.

This is the best photo I have at the moment. Since this point, I have changed oil, rebuilt the carb, polished the engine side covers (somewhat poorly), discovered I have a bad ignition coil (I think). All other electrical systems work, engine seems to have good compression, the inside of the engine was immaculate. Put in new gaskets on the engine side covers as well.

Great little project, after 40 years of not running I would recommend a full strip, clean and inspect of the engine. Seals will have hardened and the rings are probably shot, with such low mileage everything else will probably be ok with a clean and lube.

Oddly enough the rings must be a-okay because compression test reveals about 150 psi. As for oil seals, that may be the case yeah, although I will probably try to do that over the winter. yesterday I took my maiden voyage after 6 weeks of work on the bike. Finally runs well, still ironing out some likely carb issues as it did cut out once but otherwise it runs well.