On a "Wideline", the two main horizontal rails under the tank are equally spaced all the way back.
On a "Slimline", the two main rails start out wider apart at the front, and angle closer together toward the rear.
author "Old Bikes"
too many bikes to list, including:
JPN, 952 Prototype, MkIII Interstate, Combat Dunstall, VR880 SS, Triton