In this short article I will try to summarize the code used by Kawasaki for common fasteners. The ISO pitch was adopted in the 60s or 70s so the part for your motorcycle is either still available or sold under a new reference and slightly different. At Japanmotonuts.com we sell fasteners which have in general not evolved much since the 70s! We have most of the parts described here in the store, if you cannot match a reference with a product please drop me a mail.
Kawasaki uses a digit to differentiate their families of products; 1 for standard hexagon bolts, 2 for pan head screws, 3 for nuts, 4 for washers.
Two digits to identify the type of product inside a family.
A letter for the material or plating (B for bright zinc plating (called trivalent white today), G for gold is chromate plating (yellowish bolts), N is for chrome plated parts).
Finally the diameter and length of the part in mm
The letter A at the end might indicate an ISO pitch for M12 and above.
For example, 110G0825 is a standard head bolt, M8x25, in chromate plating. 13mm spanner used, 1.25mm coarse pitch.
Disclaimer: I have a Kawasaki 900 Z1 and a 750 H2 so I no know more details about them. I also used the Kawasaki Z1 & Z2 Restorer's parts book by John Brookes for reference to write this post.
Note: if you order your parts from Kawasaki you should receive a 112 upset version when asking for 110. For example if you order 110B0614 you receive 112B0614
On the Z1 and H2, code 220 is used mainly however there are a few 221 and three 222 on the front wheel.
In Kawasaki parts list there are a lot of small bolts, nuts, and washers with codes starting by 160 like 16033-009 which is an M4x16 pan-head screw with a spring washer. These are Mikuni parts for the carburetor. Until I dig-up a reference you will have to measure them!
If you can help me complete the page for other brands and models that's very appreciated, so don't hesitate to contact me.