🔧 Triumph Parallel Twin Engine
Edward Turner's 1937 Speed Twin was the most influential motorcycle engine design of the 20th century — a 499cc upright parallel twin that proved more compact, lighter, and smoother than any single-cylinder design of the era. Every subsequent British motorcycle adopted the parallel twin format. Triumph's own lineage runs unbroken: the Speed Twin (1938) became the Thunderbird 6T (1949), then the Tiger 100 (1952), then the Bonneville T120 (1959) — all sharing Turner's fundamental paired-cylinder architecture with 360° firing interval.
Engine
Especificaciones técnicas
| Type | Air-Cooled SOHC Parallel Twin (pre-unit and unit construction) |
|---|---|
| Displacement | 499 cc (Speed Twin) / 649 cc (Thunderbird) / 649 cc (Bonneville) |
| Horsepower | 27 hp (Speed Twin) / 34 hp (Thunderbird) / 46 hp (Bonneville T120) |
| Firing Interval | 360° (original) / 270° (2016+ high-frequency crank optional) |
| Carburettors | Amal TT (pre-unit) / Amal Concentric (unit) |
| Designer | Edward Turner, 1937 |
| Manufacturer | Triumph Engineering Co. Ltd., Meriden, UK |