2019-5-29 · Derbi successfully competed in Grand Prix motorcycle racing, winning 50cc world championships in 1969, 1970 and 1972.When the 50cc class was increased to an 80cc displacement in 1984, Derbi would claim four consecutive world championships between 1986 and 1989, before the class was discontinued in Grand Prix competition.The firm also experienced racing success in 125cc Grand …