Yamaha's Phil Read led Alan Barnett, Rod Gould and Dudley Robinson at the end of the first lap.
Despite spending nearly two minutes in the pits to rectify carburation problems, he won comfortably from Peter Williams (Arter Matchless) and Frank Perris on a Suzuki.
Phil Read led all the way when his main challenger Peter Williams's MZ expired at the end of the first lap.
Tony Jefferies led throughout on a works Triumph after a splendid battle with the BSA of Ray Pickrell and the Norton of Peter Williams.
Riding a Triumph, he was involved in a tremendous duel with Williams until the Norton stopped on the third lap at the Bungalow.
John Williams and Bill Smith brought Honda success in both the 500 and 250cc classes with dominant victories.
Siggi Schauzu won his fifth TT after a superb duel with BMW teammate George Auerbacher in the World Championship sidecar race.