I started a project along similar lines (FZR frame, forks, and wheels, XS650 motor) back in the late 1990's, but didn't get nearly as far as you have. The slight forward tilt of the motor should help handling a bit (don't let anyone tell you it'll cause lubrication problems, Yamaha's Ascot TT prototype tipped the motor farther than that without issues). Discovered the SV650 Suzuki before I got past a very crude mockup of motor mounting, and since the SV did what I'd wanted from the project and more, I lost motivation and gave the FZR frame to a very capable friend who may or may not have done something with it. Looking forward to seeing more of your work!