NVT/BSA Isolastic prototype.

There is an interesting feature in Classic Bike Guide Aug `12;
A `70s NVT 'Norton P 92' - which is a late BSA B50 isolastically mounted in a BSA Fury chassis, topped with roadster Commando type seat & tank.
Engine is mounted per Commando, tilted in frame.
& "on the move, achieves near- 100mph performance with little discernable vibration..."
Def` looks like something Yamaha had a hard look at before making the SR 500.

I remember that one, it had the JPN colors. Would've been a cool bike. BTW, have a look at the Peregrine Yamaha OW16 replicas. There's a short article on page 12 of CBG issue 258. Sounds like something you'd like.