Today’s invention is a secure way to carry more fuel on your motorcycle than can be accommodated in the normal tank.
An inverted U shaped tank is firmly secured to the filler cap ring of the original tank (light grey) using the red bolts indicated.
This secondary tank itself has a filler cap (green) which, when opened, allows the petrol pump nozzle (pink) to fill either the original tank, the additional one or both, to whatever levels are chosen.
This arrangement also allows fuel to be stored lower on the machine, thus making it more stable when ridden.
(How cool would it be to be able to have a secondary tank which fitted one’s own upper body: thus supporting some weight and also lessening aerodynamic drag?)