Product development had all but stopped at the Meriden Cooperative, the worker-owned organization that was heir to the Triumph name, so there were few changes to the 1977 Triumph T140V Bonneville. It had the familiar air-cooled, overhead-valve parallel twin whose displacement was established at 744cc in 1973. With twin Amal Concentric carburetors, it generated about 50 horsepower at 7,000 rpm, and the bike could do 110 mph.

The previous year, a left-side shifter was adopted, which entailed a new primary case cover. Not only did the aesthetics displease some people, but also the elaborate mechanism seemed less direct. The rear disc brake with underslung caliper was also in its second year. For 1977, the slimline tank was painted Polychromatic (also called Pacific) Blue and Cold White. The Bonneville also had a new front fender without upper braces, which resulted in a cleaner look.

Customers in the United Kingdom were offered a Silver Jubilee edition, the T140VJ Bonneville, to observe the 25th anniversary of Queen Elizabeth II’s reign. It had “upside-down” Girling rear shocks, a silver tank with blue flashes and red pinstriping, and blue seat with red piping. Each side cover featured a Silver Jubilee emblem. When the 1,000-unit run sold out in the U.K., another 1,000 were built for export to the United States. The Silver Jubilee edition was the first of the special-edition models before created before Triumph’s demise. Although Triumph’s string of five-straight Isle of Man TT production-class victories had ended after 1975, the marque’s luster still increased as tuner Jack Wilson’s turbocharged Triumph engines powered to new records at the Bonneville Salt Flats.