Despite the racing success Count Augusta insisted that the super successful four cylinder engine wasn't developed in the same way for the production series. The mistakes turned out costly for fans who were expecting a quality race bike. Instead they got the detuned 600 four which never became a huge success.
Agusta learned from the flop and in 1970 introduced the 750 Sport which was strongly orientated on the race models. This was what was expected from MV Agusta bikes and the 750 Sport was an instant success. Although it was expensive, it sold well. In following years the 750 sport was updated and in 1975 a 750S America was introduced for the US market.
The big four engines were mainly being built by hand and even though they were expensive - the firm started to have financial problems. Even the success of the big fours started to be a problem for MV Agusta. Count Agusta had passed away in 1971 due to a heart attack and, under guidance of brother Corradino, the company couldn't break out of the financial problems.
The MV Agusta motorcycle division was part of the larger MV helicopter company and by 1977 the Agusta family had lost power of the business. The last bikes were sold and in 1980 MV Agusta closed its doors.