Always a step ahead of their rivals, Triumph followed up the trend-setting Speed Twin 500 of pre-war days by being first in the field with a 650cc parallel twin. Announced in September 1949, the 650 Thunderbird was Triumph’s response to demands for more power emanating from American racers and British sidecarists, alike. A spectacular launch stunt saw three Thunderbirds lap the banked Montlhéry circuit in France at over 90mph for 500 miles, after which they each achieved a flying lap of 100mph-plus and were ridden back to the Meriden factory, a quite outstanding achievement.
Equality outstanding was a Robinson ‘Bobby’ Sirkegian. ‘Motorcycle racing was Bobby Sirkegian’s destiny. When he was six he was riding in Pee-Wee races and by the time he was 13 he had become the first AMA/NHRA Grand National Champion.’ At 13 years old, Bobby Sirkegian was already used to going 100mph. Riding tuned Triumph drag bikes sponsored by his father’s Los Angeles dealership, Sirkegian Triumph, he was a top competitor on the many quarter-mile dragstrips popping up in Southern California in the 1950s. In 1953, running at the first-ever sanctioned drag race championships in Pomona, California – what would become the NHRA Nationals – Sirkegian took wins in both the 500 and 650cc classes. The kid was a double champ at age 13! He repeated the feat the next year.
Bonneville officials knew of young Bobby’s prowess on a drag bike, and so he was given special permission to run at Speed Week in 1953. He lined up for passes in the 650cc class on a bike built very much along the same lines as his drag racers. Cylinders were bored 0.040-over, a big-bearing crankshaft was fitted, as were special-grind Iskenderian camshafts and lifters, and lightened, narrowed timing gears. A flow-benched cylinder head benefitted from enlarged intake and exhaust valves, S&W valve springs and a special manifold setup for the twin Amal carbs with attached GP-type float bowls. A BTH racing magneto provided spark. A 3-gallon fuel tank from Triumph’s 3T model carried enough gas for the salt flats speed runs. Because stopping was not a great concern but friction was, a brake-less spool hub was fitted up front.
One of the bike’s speed secrets was provided by family friend Rollie Free, famous for his record 150.313-mph ‘bathing suit’ run aboard the world’s fastest Vincent in 1948. Free gave the Sirkegians a pair of his Bonneville-ready 3×20-inch Avon ‘File Tread’ rear tires. Bobby’s 122mph pass on a 650 didn’t set any class records but he was given a special award for the being the youngest rider ever on the Bonneville Salt Flats.
Sirkegian never returned to Bonneville as a competitor. He continued drag racing, winning some 200 trophies and setting track records from California to Kansas. At 17, he gave up sprinting for the rough-and-tumble of AMA flat-track racing, but he always kept the Bonneville T6 650 pretty much as run on the Salt Flats. It was treated to a full restoration by Sirkegian himself six or seven years ago, and wears one of the ultra-rare 20-inch Avon rear land-speed tires. Also included is the brass SCTA timing tag from that infamous run at Bonneville in 1953. The Triumph remains in museum-quality to this day.
Report by bonhams.com