Triumph Bonneville 750 T140E Special Edition


Make Model

Triumph Bonneville 750 T140E Special Edition




Four stroke, parallel twin, OHV, 2 valves per cylinder


744 cc / 45.4 cu in
Bore x Stroke 76 x 82 mm
Compression Ratio 8.6:1
Cooling System Air cooled


2 x 30 mm Amal carburetors


Battery / dual coil / dual points / Lucas


Electric and kick

Max Power

40.3 kW / 54 hp @ 6200 rpm

Max Torque

56.6 Nm / 5.77 kgf-m / 41.8 ft-lb @5500 rpm


Wet, multiplate


5 Speed

Final Drive

Chain, 106 links

Gear Ratios

1st 12.25 / 2nd 8.63 / 3rd 6.58 / 4th 5.59 / 5th 4.70:1
Frame Tubular steel, double front downtubes, oil bearing large tube backbone

Front Suspension

Telescopic forks

Rear Suspension

Swingarm, Girling shocks, 3-way spring preload adjustable

Front Brakes

Single 254 mm disc, 1 piston caliper

Rear Brakes

Single 254 mm disc, 1 piston caliper

Front Tyre


Rear Tyre

Rake 28o
Trail 109 mm / 4.3 in
Wheelbase 1422 mm / 56 in
Dimensions Length: 2220 mm / 87.5 in
Width:    840 mm / 33.0 in
Seat Height 813 mm / 32.0 in

Dry Weight

200 kg / 441 lbs

Fuel Capacity 

18.2 Litres / 4.8 US gal / 4.0 Imp gal
Consumption 5.5 L/100 km / 18 km/l / 42 US mpg / 51 Imp mpg
Top Speed 190 km/h / 118 mph

When Edward Turner was pencilling his design for the Triumph Speed Twin way back in the mid-1930s he could scarcely have dreamed that the same basic design would be used to power a superbike of the 1970s, the Triumph Bonneville 750. The fact that the Bonneville lasted so long is a tribute to the men at Meriden who, when their factory was threatened with closure during the early 1970s, engaged in a marathon sit-in which saved the works, their jobs, and their beloved Bonneville for another decade.


By 1978, however, the Bonneville was something of an anachronism in the world of motor cycling. It had an old-fashioned twin-cylinder, pushrod engine in a world dominated by multi-cylinder machines from Japan. Astonishingly, the Bonneville was still the best selling 750 in Britain during 1978 in spite of the fact that this was one of the most competitive classes on the market. Much of this success was due to the absolute simplicity of the Bonneville. Weighing about 395lb it was about a hundredweight lighter than most of its Japanese rivals and with a crankcase measuring about 14 inches across it was a good eight inches narrower than the bulkier Japanese fours.


This light weight and slim build also meant that the bike's manoeuvrability and handling were far superior to most of its rivals, a fact that went down well with British riders confined to roads narrower, shorter and more crowded than those of their colonial cousins.


The powerhouse of the Bonneville is a straightforward piece of machinery. Two cylinders, each measuring 76 mm by 82 mm, give a total capacity of 744cc-the original Bonneville models, incidentally, were of 650cc but were uprated for more power and torque—while the valves are operated by pushrods. Two Amal carburettors provide the fuel for the 8.6:1 compression ratio motor, giving a power output of 49 bhp at 6200 rpm, not a great deal by modern Japanese standards. Where the Bonneville scores over the Japanese multis, however, is that the engine offers usable torque even at the lowest revs. The only serious problem surrounding the Bonneville is the classic one common to most parallel twins—vibration. At high revs the bike vibrates quite severely, sending tingling sensations through the rider's arms and shoulders which at times may even become painful.


Another criticism levelled at the Bonneville is that its engine leaks oil. Models produced by the Meriden cooperative, however, are a far cry from those oldoil burners of the 1950s and the average owner has little to complain about in that respect.


Visually the Bonneville changed little over the years. It retained that lean and lithe look that is so typically British and which made it so popular over the years. The paint finish on the tank, much of it hand applied at the factory, is superb. Indeed, the bike is immaculately finished, living proof of the loving care and attention that went into the building of these machines.


The Bonneville may not have had the performance or sophistication of its multi-cylinder oriental rivals but it did have something that most of them lack, an almost human personality of its own—idiosyncratic, occasionally unreliable but always friendly.