Featured Pages Ariba Ariba Supercharged 500cc DOHC Watercooled Four, 1928
Riva FourThree at a Squeeze Strange scooter/motorcycle contraption
Atlanta DuoDestined for Legend Road Tests of New Models
Astro Bicycle Engines
A Brief History of the Italian Marque
The Astro auxiliary motor is a horizontal single cylinder 47cc two-stroke. Another source indicates production until 1955.