Built around Triumph's allround motorcycle platform, the 1964 Triumph Bonneville T120C Street Scrambler utilizes a 649 cc (39.6 cu in) air-cooled twin, four-stroke layout. In factory specification, peak output is rated at 46 HP (33.6 kW) at 6,500 rpm, transferring power to the rear wheel through a 4-speed gearbox and chain final drive. With a specific output of 70.9 HP per liter, the engine character is indicating a tractable, stress-free state of tune focused on everyday usability and broad torque delivery.
On the scales, the Bonneville T120C Street Scrambler measures 165 kg (364 lbs) dry, translating to a power-to-weight ratio of 0.28 HP/kg (3.59 kg per horsepower). Rider ergonomics and chassis geometry center around a 775 mm (30.5 in) seat height — offering a neutral standover height that accommodates most average-inseam riders without sacrificing cornering clearance, combined with a 1,403 mm (55.2 in) wheelbase engineered for quick, flickable steering geometry. The 15.14-liter (4 US gal) fuel tank supports practical everyday commuting and weekend road stints, while factory top speed is listed at 185 km/h (115 mph).
Within MotoLibrary's Triumph archive, this model family spans 7 indexed model years from 1963 to 1969, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Specific Output
70.9 HP/L
Power-to-Weight
0.28 HP/kg (3.59 kg/HP)
Standover Height
775 mm (30.5 in)
Engine
Displacement649.0 ccm (39.60 cubic inches)
Engine TypeTwin, four-stroke
Engine DetailsTwin, four-stroke
Power46.0 HP (33.6 kW)) @ 6500 RPM
Compression8.5:1
Bore x Stroke71.0 x 82.0 mm (2.8 x 3.2 inches)
Fuel SystemCarburettor. Amal monobloc carburettor
Fuel ControlOverhead Valves (OHV)
IgnitionLucas K2F auto-advance Magneto
CoolingAir
Transmission
Gearbox4-speed
Final DriveChain (final drive)
ClutchMulti-plate, wet
Performance
Top Speed185.0 km/h (115.0 mph)
Chassis
Frame TypeBrazed lug, full-cradle, single downtube
Rake26.0°
Front SuspensionTelescopic fork, hydraulic damping.
Rear SuspensionSwing arm, 2 Girling dampers
Wheelbase1403 mm (55.2 inches)
Ground Clearance127 mm (5.0 inches)
Wheels & Brakes
Front Tyre3.25-19
Rear Tyre4.00-18
Front BrakesExpanding brake (drum brake)
Front Brake Ø203 mm (8.0 inches)
Rear BrakesExpanding brake (drum brake)
Rear Brake Ø178 mm (7.0 inches)
WheelsWire spoked
Dimensions & Weight
Dry Weight165.0 kg (363.8 pounds)
Power/Weight0.2788 HP/kg
Seat Height775 mm (30.5 inches) If adjustable, lowest setting.
Fuel Capacity15.14 litres (4.00 US gallons)
Other
StarterKick
Color OptionsGold/White
ElectricalLucas RM19 alternator, 6-volt electrical system
Use this page to compare this motorcycle by its real specifications, not only by model name. Focus on the details that affect fit, comfort, handling, range and ownership.
Power
Compare engine output with similar motorcycles if acceleration, highway use or two-up riding matters.
Seat Height
Check the seat height against your inseam and riding posture before choosing a motorcycle.
Weight
Compare weight carefully because it affects low-speed handling, parking and confidence.
Fuel Capacity
Fuel capacity helps estimate touring range and how often you may need to stop.
Brakes
Brake setup is worth comparing if you ride in traffic, mountains or with a passenger.
Suspension
Suspension details can matter for comfort, road feel and long-distance riding.
Transmission
Transmission and final drive affect maintenance, smoothness and everyday usability.
