After 3 years of study, a new engine works for days on the bench, and after having tested it in September 1929, Ollearo prepares the revolutionary motorbike called “Tipo 4” of 175 cc. just in time to show it at the Turin Cycle and Motorcycle Fair in March 1930.
The particular characteristics (innovative for the national production of those years) are the 4-stroke of 175 cc. (60×61.5) engine with transversal rotation, overhead valves, the 4-speed in-block gearbox and the cardan transmission.
The frame is a double cradle built by folding a single tube over 5 meters long, parallelogram fork, electric system with sparking ignition; instruments on the tank including clock and odometer are available on request.
In March 1931 arrives the natural evolution of the “Type 4”: a 350 cc motorcycle. called “Siren” that differs from the 175 cc for a larger crankcase, and for the head which two exhaust pipes are applied.
In March 1932 Ollearo presents the NEW motorcycle “Pearl”: on the crankcase and chassis of the Sirena 350 cc., Modifying the crankshaft, cylinder and head, reaches the of 500 c.c. (stroke and bore arrives at the “framework” of 86×86).
In March 1933, according to the same scheme, a 250 cc (68 x 68) motorcycle was added to the production, it differs from 175 cc. only for the cylinder and the carburetor of greater diameter.
In 1946 the frames of all the 4-stroke motorcycles were modified by constructing a rear elastic suspension with a built-in hydraulic shock absorber and a telescopic hydraulic front fork. Tank and mudguards were also modified to make the line more modern, increased the diameter of the brakes, and the power of the engines by applying aluminum heads and cylinders.
Like 2-stroke moto-vans, the production of 4-stroke motorcycles is flanked by a production of vehicles with three wheels but in this case with the front directional and the two rear with differential and cardanic transmission.
The production of motor-vans is very diversified: containers and body of different sizes can be set up on different engines, closed or open, with or without a driving cab; special barrel tanks for liquids or “tipper truck” supplied for example to the Municipality of Turin for garbage service.
In 1952 “Ollearo – Fabbrica Italiana Motoveicoli e Autoveicoli” ceased its activity of building motorcycles, taking care of only spare parts and repairs, dedicating itself to other activities.