YPVS adopted, Kenny wins his first GP title
This model 0W35K used secretly in the latter stages of the 1977 season was the first to adopt YPVS (Yamaha Power Valve System), which controlled exhaust timing to largely eliminate the torque valleys in the power development. This improved lap times dramatically for Johnny Cecotto, who scored consecutive wins at the Finland GP and Czechoslovakia GP and finished the 1977 season ranked 4th. The next year, 1978, Kenny Roberts won four of the 11 rounds to win the first of his three consecutive World GP 500 titles.
- Capacity - 497cc
- Max Power - 105PS
1st: 2 Johnny Cecotto - Finland, Czechoslavakia