Triumph 6T Thunderbird (1954-62)

The Triumph 6T Thunderbird was a motorcycle produced between 1954 and 1962. It had a four-stroke, vertical twin, overhead valve engine with a capacity of 649cc and a compression ratio of 8.5:1 (export) or 7.0:1 (UK). It had a 4-speed constant mesh transmission and a wet, multiplate clutch. The bike had a maximum power output of 25kW or 34hp at 6500rpm. The frame was brazed lug with a telescopic fork, hydraulic damping front suspension and a swingarm, 2 griling dampers rear suspension. The front and rear brakes were SLS drum with an 8in and 7in diameter respectively. The bike had a wheelbase of 1410mm or 55.75in and a dry weight of 179kg or 395lbs. The fuel capacity ranged from 13.6L or 3.6US gal/3.0Imp gal (US) to 18L or 4.8US gal/4.0Imp gal (UK and export). Overall, the Triumph 6T Thunderbird was a powerful and sturdy bike that was popular with riders during its production years.

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Technical specifications:

Make Model: Triumph 6T Thunderbird

Year: 1954 – 62

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: SU type MC2

Ignition: Lucas RM14

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: Swingarm, 2 Griling dampers

Front Brakes: SLS drum, 8 in

Rear Brakes: SLS drum, 7 in

Front Wheel: 3.25 x 19

Rear Wheel: 3.50 x 19

Wheelbase: 1410 mm / 55.75 in

Seat Height: 775 mm / 31 in

Ground Clearance: 127 mm / 5.0 in

Dry Weight: 179 kg / 395 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