1983 yamaha xs400 seca

 square everything
 engine doubles as a structure member whereas the YICS combustion chamber forces the intake charge to tumble into the combustion chamber.
 A disc brake up front and a two-into-one exhaust.
The triangulated swingarm is suspended by a single shock the makes with the frame's backbone.
The forks came stock with a brace to reduce the likelihood of having your forks twist under heavy braking.
 Still need to find a gas cap.
The gas tank isn't stock, nor are the clubman bars.
 8-point mag wheels aren't too common.