Engineered by Triumph for the sport motorcycle segment, the 1969 Triumph Boneville T120R Roadster relies on a 649 cc (39.6 cu in) air-cooled engine powerplant. In factory specification, peak output is rated at 49 HP (35.8 kW) at 6,200 rpm, transferring power to the rear wheel through a 4-speed gearbox and chain final drive. With a specific output of 75.5 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 Boneville T120R Roadster measures 165 kg (364 lbs) dry, translating to a power-to-weight ratio of 0.3 HP/kg (3.37 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 mm (0 in) wheelbase engineered for quick, flickable steering geometry. The 9.46-liter (2.5 US gal) fuel tank supports practical everyday commuting and weekend road stints, while factory top speed is listed at 185 km/h (115 mph).
Specific Output
75.5 HP/L
Power-to-Weight
0.3 HP/kg (3.37 kg/HP)
Standover Height
775 mm (30.5 in)
Engine
Displacement649.00 ccm (39.60 cubic inches)
Engine DetailsTwin, four-stroke
Power49.00 HP (35.8 kW)) @ 6200 RPM
Compression9.0:1
Bore x Stroke71.0 x 82.0 mm (2.8 x 3.2 inches)
Fuel SystemCarburettor. Amal Concentric carburettor
Fuel ControlOverhead Valves (OHV)
IgnitionLucas
CoolingAir
Transmission
Gearbox4-speed
Final DriveChain
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
Wheelbase1,403 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). Twin Leading Shoe
Front Brake Ø203 mm (8.0 inches)
Rear BrakesExpanding brake (drum brake)
Rear Brake Ø178 mm (7.0 inches)
WheelsWire spoked. Dunlop tyres.
Dimensions & Weight
Dry Weight165.0 kg (363.8 pounds)
Power/Weight0.2970 HP/kg
Seat Height775 mm (30.5 inches) If adjustable, lowest setting.
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.
