Triumph drew on the experience gained from developing the 865cc parallel-twins and the 2,294cc Rocket III engines, when developing the new unit, with most of the design team coming from these projects. The team employed the same care and expertise used in the class-leading Daytona 675 supersport machine, ensuring a throughout modern and efficient powerplant for the new machine.
The double overhead camshaft engine features four valves and twin spark plugs per cylinder and, to aid starting, the exhaust camshaft is equipped with a decompression system.
A 270° crankshaft was chosen to deliver the aural experience expected by cruiser riders, with the bike delivering a satisfying thump through its classically styled twin exhaust pipes. The sound and feel of the T-16 unit was paramount in the design brief and despite having two 800cc pistons thudding up and down inside the bores, the engine delivers its power in a refined manner thanks to twin balancer shafts, which are situated in front of, and behind, the cylinders, as well as a torque compensator fitted to the end of the crankshaft.
The team worked on eliminating high pitched mechanical sounds and embracing the low bellows that characterize a big capacity twin, with the silencers being designed to let as much low frequency ‘boom’ through as is possible under the emissions regulations. Helically cut gears, from second to sixth, reduce lash and mechanical noise and the net result is a motor that is smooth but with a pleasant low-down power delivery and engine tone that makes the rider feel connected to the motorcycle.
Controlling noise and gas emissions is critical in any modern engine design, so liquid-cooling was an automatic choice for the new engine. Fuel is delivered through twin 42mm diameter throttle bodies and the intelligent electronic fuel injection system, similar to that employed on the Daytona 675, reacts to the rider input to give the Thunderbird automatic ‘sport’ and ‘cruise’ modes.
Gentle application of the throttle results in an equally soft and smooth power delivery, while the ECU recognizes rapid openings and subsequently delivers maximum available punch. Each cylinder has its own oxygen sensor and runs a separate fuel injection map, with the intelligent closed-loop electronic fuel injection ‘learning’ how the engine is running and constantly adapting to ensure the motor runs as smooth and efficiently as possible. Catalytic converters ensure that the Thunderbird complies with all the latest emissions regulations.
Despite having massive torque that keeps gear shifting to a minimum, the Thunderbird has been equipped with a refined six-speed gearbox to give a lazy overdrive for optimum fuel consumption on laidback cruises. Thunderbird is the first belt driven Triumph of the Hinckley era and indeed the marque’s first since the mid-1920s, when motorcycles using rudimentary leather belts were phased out, and this latest machine’s system has been designed for excellent durability thanks to a tungsten carbide treatment on the rear pulley.
As well as delivering class leading performance, the T-16 engine has been designed to look as good as it sounds. The cam chain is driven by an idler gear, allowing the camshaft sprockets to be smaller and ensuring that the cylinder head remains in perfect proportion to the bottom end.
