Triumph 6T Thunderbird (1950-53)

The Triumph 6T Thunderbird was a 1950-53 motorcycle that featured a four-stroke, vertical twin, OHV engine with a capacity of 649cc. It had a compression ratio of 8.5:1 (export) or 7.0:1 (UK) and was air-cooled. The motorcycle had an output of 25 kW / 34 hp at 6500 rpm and a 4-speed constant mesh transmission with a wet, multiplate clutch. The bike had a rigid, spring-loaded saddle and a telescopic fork with hydraulic damping for suspension. Its front and rear brakes were SLS drums, 7 inches in size, and the motorcycle had a wheelbase of 1403mm / 55.25in. The Triumph 6T Thunderbird weighed around 168kg / 370lbs and had a fuel capacity of 13.6L / 3.6 US gal / 3.0 Imp gal (US), 18L / 4.8 US gal / 4.0 Imp gal (UK and export).

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Technical specifications:

Make Model: Triumph 6T Thunderbird

Year: 1950 – 53

Engine: Four stroke, vertical twin, OHV

Capacity: 649 cc / 40.0 cu in

Bore x Stroke: 71 x 82 mm

Cooling System: Air cooled

Compression Ratio: 8.5:1 (Export), 7.0:1 (UK)

Exhaust: Two-into-two

Induction: 1 x Amal Monobloc, 25 mm (1953: SU type MC2)

Ignition: Lucas magneto

Starting: Kick

Max Power: 25 kW / 34 hp @ 6500 rpm

Clutch: Wet, multiplate

Transmission: 4-Speed constant mesh

Final Drive: Chain, 101 links

Gear Ratios: 1st 11.90:1 / 2nd 8.25:1 / 3rd 5.81:1 / 4th 4.88:1

Frame: Brazed lug

Front Suspension: Telescopic fork, hydraulic damping

Rear Suspension: Rigid, spring loaded saddle

Front Brakes: SLS drum, 7 in

Rear Brakes: SLS drum, 7 in

Front Wheel: 3.25 x 19

Rear Wheel: 3.50 x 19

Wheelbase: 1403 mm / 55.25 in

Seat Height: 775 mm / 31 in

Ground Clearance: 127 mm / 5.0 in

Dry Weight: 168 kg / 370 lbs

Fuel Capacity: 13.6 L / 3.6 US gal / 3.0 Imp gal (US), 18 L / 4.8 US gal / 4.0 Imp gal (UK and export)

Source: Classic British Motorcycles