Roberto wrote: I don't know the history of Ducati, but at that time, early mid 70s ...
It wasn't a particularly happy time in Bologna. Things started well, with the widely publicized success at Imola in 1972 and the sales increase that followed - 1973 was the peak year for 750 production/sales. The factory was expanded in late 1972-73, and this caused some interruption in production of the singles (it may well have contributed to the decision to switch the production of all the components for the 250 Scramblers and the engines for the 350s to Mototrans in Spain).
Then in 1973, the company got a new Director, Christiano De Eccher. De Eccher wasn't a motorbike enthusiast like his predecessors, Arnaldo Milvio and Fredmano Spairani. He also had a clear mandate from the state company who owned Ducati (EFIM) to increase production and reduce costs in order to make the company profitable. One of his first acts was to stop Ducati's participation in racing. Building the singles was an expensive business so, with sales declining in the US,THE critical market for Ducati, it was decided to axe both them and the round-case 750, also considered too expensive to build. In October 1973, De Eccher announced that the low cc singles were to be replaced by the so-called Parallel Twins and the 750s by the cheaper-to-build and re-styled square-case twins, notably the 860GT.
History has proved that both decisions were catastrophically wrong and almost finished the company off. If it hadn't been for Ign Taglioni's insistence on continuing to work on the development of the belt-drive Pantah engines; and the artistic genius of Leopoldo Tartarini, it would have been.