In 1960 Kawasaki Aircraft acquired part of the largest motorcycle manufacturer in Japan, Meguro. Meguro had a license to produce the BSA A7 and Kawasaki’s money allowed them to introduce it to the world. In 1963 Kawasaki completed the takeover of Meguro and by 1966 had brought out the W1.
Based on the BSA A7, the Kawasaki featured many motor improvements including a short stroke, one piece crankshaft that was roller bearing mounted. The short stroke took a lot of load off the crankshaft and allowed for much higher rpm. Though the motor looks like the BSA it is significantly different internally.
This bike was produced in 1965 and sold in North America as a 1966. The 650cc motor was the largest produced in Japan at the time. It was big and fast and relatively smooth. Kawasaki made some styling changes that made this bike a clear departure from either the Meguro or BSA line. It was the start of the Kawasaki brand.
Another example of the W1, photo from Wikipedia.
It’s a rare bike, and I think I have only seen one out in the real world. In 1972 I had a good buddy that ordered the first Z1 that I had ever seen. He and I went to the dealership where he ordered the Z and there was a W1 in the used line. I was riding a Triumph twin at the time and I looked the Kawasaki over very closely. I held off, and ended up with a Z1 of my own.
If you are interested in owning a unique piece of Japanese motorcycle history, this bike is available right here on Cycle Trader in Citra, Florida for $8,900.