Engine management for the ignition and EFI with twin 42mm throttle bodies controls each cylinder separately, and at our 42.0-mpg average the bike seems more fuel efficient than most. Power flows to the wide rear 200-series radial from the liquid-cooled, DOHC, four-valve-per-cylinder engine through a six-speed transmission with quiet helical gears and belt final drive, Triumph’s first belt since the 1920s. Triumph focused on elemental sound, power and simple rider-friendliness in designing the new Thunderbird. And if it’s still not enough, Triumph offers a road-legal 1,700cc big-bore kit that it claims is good for 5 more horsepower and 7 more lb-ft. That’s some nice rumble indeed, even compared to much larger V-twins. On the Jett Tuning Dynojet dyno, our 2010 Thunderbird cranked out 74 horsepower and 93 lb-ft at the rear wheel. That’s a big leap from Triumph’s original 649cc 1950 6T Thunderbird that Marlon Brando rode in The Wild One, or even the reborn 1995 Thunderbird 885cc triple, which made about 70 horsepower and 53 lb-ft of torque at the crankshaft. In fact, it’s now the largest parallel twin in production. Well, if you want something to rumble when it rolls and it’s not a V-twin, just make it bigger, right? Enter the 2010 Triumph Thunderbird, at 1,596cc nearly double in engine size over Triumph’s other twin-cylinder cruisers. Although the 865cc America and Speedmaster have 270-degree crankshafts instead of the Bonneville’s 360 crank for an offbeat, gruntier sound, they’re still known more for power and smoothness for their engine size rather than the traditional “rumble” that cruiser riders crave. Yet Triumph’s year-2009 cruisers are all powered by either an enormous in-line triple (Rocket 3) or the ducky parallel twin from the Bonneville. If that’s not indicative of what the American cruiser rider wants, I don’t know what is. lineups, you can count those with something other than a V-twin engine on one hand. For example, among the nearly 100 cruisers in the other manufacturers’ U.S.
Photography by Kevin Wing 2010 Triumph Thunderbirdĭespite competing head-to-head with much larger makers for a slice of the American motorcycle market, Triumph has always gone its own way.