Hugh Anderson was the favourite to win the 125 race as he had been winning all season on his redesigned Suzuki . However Anderson was forced to retire with mechanical trouble, as had his team-mate Frank Perris . This left Ernst Degner as the sole works Suzuki rider and he led Klaus Enderlein, Derek Woodman (M.Z.s) and Ralph Bryans (Honda) for the rest of the race, finishing almost 3 minutes ahead of Enderlein . He also set the fastest lap of the race at 90.84 mph (145.30 km/h) .
The 500 race was minus M.V. which meant Mike Hailwood and his new team-mate Giacomo Agostini were missing . From the drop of the flag a scrap developed straight away with Paddy Driver (Matchless), Chris Conn (Norton) and John Cooper (Norton) each looking to lead . Less than a second separated them for the first 3 laps . Then on lap 4 Cooper suffered mechanical trouble and had to retire . Dick Creith, meanwhile, was working his way up through the field on his Norton when rain started to fall on parts of the course . The leading duo slowed down but Creith continued at the same speed and quickly reeled them in and passed them . He was 8 seconds ahead of Driver who managed to get ahead of Conn to take 2nd place . Driver had the consolation prize of having set the fastest lap of the race at 91.49 mph (146.38 km/h) . Creith was the first Ulsterman to win the Senior race at Dundrod .