Go to http://www.kawasaki.com Since you've gotten this far I'll assume you can follow basic browser navigation and may have omitted some of the most obvious steps below.
click on "Owner Info>Parts Diagrams
Motorcycle selected by default. Click continue
Select model and year if you want. You'll be asked which year later if you don't choose it.
Click on "Parts Diagrams"
A new window will popup with the parts diagrams. you may need to adjust your popup settings or just click the link indicated.
Parts catalog. browse to the part your looking for. In my case it is the junction box. click on the part link for details you should see something similar to the picture below.
If you click on the yellow circled question mark, you will get a list of models that also use that part in another window as shown on the right. If you see a red circled "S" next to a part that means it has been superseded. Click on the red circle to get superseded part numbers.
