I've a 5665 with a 12
hp Kohler engine. It was difficult to steer with and without the duals. What it needed, and now has, is steering brakes. The one shown in the picture has no brake bar. It could be the 8
hp, which would be a little lighter in weight.
Attached is a picture of mine before the duals but with the brake bar over the left side handlebar.
Ralph