| MODEL | TRIUMPH THUNDERBIRD 6T 1963 - 1966 |
| Year | 1963 - 1966 |
| Engine Type | Four stroke, vertical twin, OHV |
| Displacement / Capacity | 649 cc / 40.0 cu in |
| Bore X Stroke | 71 x 82 mm |
| Compression Ratio | 8.5:1 |
| Cooling System | Air cooled |
| Max Power | 31 kW / 42 hp @ 6500 rpm |
| Max Torque | — |
| Ignition | — |
| Induction | Amal Monobloc |
| Start System | Kick |
| TRANSMISSION SPECS | |
| Lubrication | — |
| Gear Box | 4-Speed constant mesh |
| Clutch | Wet, multiplate |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | Brazed lug |
| Front Suspension | Telescopic fork, 2 way hydraulic damping |
| Rear Suspension | Swingarm, 2 hydraulic dampers |
| Front Brakes | SLS drum, 8 in |
| Rear Brakes | SLS drum, 7 in |
| DIMENSION SPECS | |
| Overall Length | — |
| Overall Width | — |
| Overall Height | — |
| Seat Height | 825.5 mm / 32.5 in |
| Wheelbase | 1384 mm / 54.5 in |
| Ground Clearance | 127 mm / 5.0 in |
| Dry Weight | 165 kg / 363 lbs |
| Wet Weight | — |
| WHEEL SPECS | |
| Front Tyre | — |
| Rear Tyre | — |
| FUEL SYSTEM | |
| Fuel Capacity | — |
| Fuel Consumption | — |
| Top Speed | — |
The 1963 Thunderbird was the first 650 Thunderbird to use Triumph's unit-construction engine, with engine, primary drive and gearbox in a single casting. It also gained a new single-downtube frame and revised forks and brakes. It kept its familiar nacelle headlamp styling and remained a relaxed, tourer-style 650 twin until production ended in 1966.
