Anyone have links to a forum and/or tech data on the xs400? Are the xs400 and the 650 the same, other than CC?.
Tons of info if you google XS400, but to answer your question, no. The 400 was designed from the ground up to compete in the fast growing (well, in other parts of the world than the North American market) 'mid range' market. It's competition was the Suzuki GS400/425, Honda 400 and Kawasaki 400/440.
The engine has more sophistication than the 650.