Triumph T120 Bonneville (1972-73)

The Triumph T120 Bonneville was a motorcycle produced in 1972-73 with a four-stroke, parallel-twin, OHV engine and a capacity of 649 cc. It had a compression ratio of 9.0:1, air-cooled cooling system, and 2 x 30 mm Amal concentric carburettors. The bike was built with battery coil ignition and a kick starting mechanism, and had a 12V alternator lighting system. The oil system used a double plunger pump with a dry sump, and had a capacity of 3.4L. The multi-disc, wet clutch produced a maximum power of 37.3 kW at 7000 rpm, with a maximum torque of 52.1 Nm at 6000 rpm.

The 4-speed transmission had a final drive chain, and gear ratios of 1st: 12.08, 2nd: 8.36, 3rd: 6.14, and 4th: 4.95. Suspension was provided by telescopic forks at the front and a swinging arm with dual shocks at the rear. The front and rear brakes were both drum brakes, and the bike weighed 181kg with a wet weight of 399lbs. It had a fuel capacity of 16L and was designed with a classic and iconic style.

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Technical specifications:

Make Model: Triumph Bonneville 650 T120

Year: 1972 – 73

Engine: Four stroke, parallel twin, OHV

Capacity: 649 cc / 39.6 cu in

Bore x Stroke: 71 x 82 mm

Compression Ratio: 9.0:1

Cooling System: Air cooled

Induction: 2 x 30 mm Amal concentric carburetors

Ignition: Battery, coil

Starting: Kick

Lighting system: 12V alternator

Oil system.: Double plunger pump, dry sump

Oil capacity: 3.4 L / 7.2 US pt / 6 Imp pt

Clutch: Multi-disc, wet

Max Power: 37.3 kW / 50 hp @ 7000 rpm

Max Toque: 52.1 Nm / 5.3 kgf-m / 38.5 lb-ft @ 6000 rpm

Transmission: 4 Speed

Final Drive: Chain

Gear Ratios: 4th 4.95 / 3rd 6.14 / 2nd 8.36 / 1st 12.08

Front Suspension: Telescopic forks

Rear Suspension: Swinging arm, dual shocks

Front Brakes: Drum

Rear Brakes: Drum

Front Tyre: 3.25 -19

Rear Tyre: 4.00 -18

Fuel Capacity: 16L / 4.2 US gal / 3.5 Imp gal

Wet Weight: 181 kg / 399 lbs