NOTE: Found this on eBay. The words are the owner's:

In the rear, a Concours wheel hub was turned down and a
1992 Suzuki GSXR 750 wheel machined to fit and welded
to the Kawasaki center, allowing stock Kawasaki brakes
and drive to be used. It is a 4.50 X 17 in. rim with a
160\70x17 tire.