The series had previously been run as a British competition under ACU rules.
Although disqualified at Silverstone for using a different bike in the second race,[2] Barry Sheene won the championship.
The Ontario Motor Speedway in California, US was scheduled to hold a round in May 1973.
Due to financial difficulties and management changes the event was rescheduled to October.
Suzuki objected and the points awarded were based on positions in each race.