1951 was the third year of production for Triumphs first 650cc twin 649cc/35 HP OHV parallel twin-cylinder engine 4-speed manual transmission Right-side foot shift Chain primary and final drive Sprung solo saddle and pillion pad Telescopic front fork Front 6-inch single-leading shoe drum brake Rear 6-inch single-leading shoe drum brake 3.25-19-inch front and 4-19-inch rear tires Marlon Brando rode a Triumph Thunderbird in the 1953 film The Wild One For more information, please visit mecum.com.