While Ossa was busy developing their off-road line in the mid-1960s, the son of the owner Eduardo Giró decided they should also go roadracing. He designed a simple 250 cc rotary disc two stroke single to compete against the might of the Japanese. It featured huge fin area for cooling, an enormous for-the-time 42mm Amal carb. Even the exhaust was oversize. This engine was installed in a welded aluminum monocoque chassis resulting in a lightweight racer that held it's own in 250 GP during 1968 and 1969 by which time the engine was producing 42 hp. In the hands of Santiago Herrero the bike managed 3 first places and several podiums in 1969 and they finished 3rd in the championship. The 1970 season got off to a great start but when Herrero crashed and was killed in the Isle of Man TT Ossa withdrew from racing. The motorcycle is currently on display in the Barcelona Motorcycle Museum.
Mick Walker, Spanish Postwar Road and Racing Motorcycles, Osprey Publishing 1986