For the 1966 season, Mike Hailwood changed from MV to Honda. And so, Giacomo Agostini will stay alone to defend the colors of MV-AGUSTA. Quickly the 500 4 cylinders, in end of development, will acknowledge its limits facing the new 500 Honda. Moreover Ago didn't like this bike. For the 3rd GP of the season at Assen, decision was made to use the base of the 350 3 cylinders to develop a new 500. The first 500 MV-3 was a rebored 350 (380 cm³, it evolves then up to 470 cm ³, to become a true 500 the next year). The first GP of this bike was a fight between Ago and Redman. Obviously this bike had been well born and the first World Champion title of Agostini at the end of the year was the best proof.
Agostini was also titled from 1967 to 1972 with this bike, which built up its legend. 1973 was a year of transition between the 3 cylinders and the new 4 cylinders. Phil Read with MV was titled. The change for Agostini to Yamaha in 1974 put an end to the Ago-MV legend, and this, in spite of an ultimate attempt for the season 1976.
Agostini won its last GP at the Nürburgring the same year with the 500 MV 4 cylinders, on the same track he triumphed for the first time with MV, eleven years earlier.