The Triumph Bonneville T120R Roadster motorcycle specifications include a 649 cc (39.60 cu in) engine, power of 46 hp (33.6 kW) @ 6,500 rpm, a 4-speed gearbox, and a listed weight of 165 kg (363.8 lb).
Key specifications
The 1963 model is treated as the standard specification. Only later model years with a different supplied value are shown below.
How the Triumph Bonneville T120R Roadster compares
This compares the motorcycle with all Triumph models in this specifications database. The blue marker is this model and the grey line is the Triumph database average.
About 47% lower than the Triumph database average. Around the 15th percentile across Triumph models.
About 32% lower than the Triumph database average. Around the 18th percentile across Triumph models.
Very close to the Triumph database average. Around the 36th percentile across Triumph models.
About 15% smaller than the Triumph database average. Around the 22nd percentile across Triumph models.
Triumph database percentile rankings
Percentiles show where this motorcycle sits across the Triumph specifications database. They are descriptive database rankings, not performance ratings.
46 hp — more powerful than about 15% of Triumph models with power data.
649 cc — larger displacement than about 18% of Triumph models.
775 mm — taller than about 36% of Triumph models.
15.1 L — larger than about 22% of Triumph fuel tanks in this database.
Dimensions compared with Triumph average
Each measurement is compared with the average value across Triumph models where that dimension is available.
1,403
1,491
6% below average.
775
789
Close to average.
127
124
Close to average.
Mechanical overview
Additional useful specifications
| Front tire size | 3.25-18 |
|---|---|
| Rear tire size | 3.50-18 |
| Power-to-weight ratio | 0.279 hp/kg |
| Power-to-weight | 278.8 hp/tonne |
| Specific power | 70.9 hp/L |
| Bore/stroke ratio | 0.87:1 (Undersquare) |
Engine specifications
| Engine type | Twin, four-stroke |
|---|---|
| Displacement | 649 cc (39.60 cu in) |
| Power | 46 hp (33.6 kW) @ 6,500 rpm |
| Bore × stroke | 71.0 x 82 mm (2.8 x 3.2 inches) |
| Compression ratio | 8.5:1 |
| Cooling system | Air |
| Fuel system | Carburettor. Amal monobloc carburettor |
| Fuel control | Overhead Valves (OHV) |
| Ignition | Lucas K2F auto-advance Magneto |
| Starter | Kick |
Transmission and drivetrain
| Gearbox | 4-speed |
|---|---|
| Final drive | Chain (final drive) |
| Clutch | Multi-plate, wet |
Chassis and suspension
| Frame | Brazed lug, full-cradle, single downtube |
|---|---|
| Front suspension | Telescopic fork, hydraulic damping. |
| Rear suspension | Swing arm, 2 Girling dampers |
| Rake | 26.0° |
Brakes, wheels and tires
| Front brakes | Expanding brake (drum brake) |
|---|---|
| Rear brakes | Expanding brake (drum brake) |
| Front tire | 3.25-18 |
| Rear tire | 3.50-18 |
| Wheels | Wire spoked |
Dimensions and weight
| Dry weight | 165 kg (363.8 lb) |
|---|---|
| Seat height | 775 mm (30.5 inches) |
| Wheelbase | 1,403 mm (55.2 inches) |
| Ground clearance | 127 mm (5.0 inches) |
Fuel and emissions
| Fuel capacity | 15.14 L (4.00 US gal) |
|---|
Performance
| Top speed | 185.0 km/h (115.0 mph) |
|---|---|
| Power/weight ratio | 0.2788 hp/kg |
Electrical and instruments
| Electrical | Lucas RM19 alternator, 6-volt electrical system |
|---|
Other specifications
| Color options | Alaskan White |
|---|---|
| Seat | Dual seat |
Disclaimer: Specifications may vary by market, trim, production date and optional equipment, and scraped or historical data can contain errors. Comparison and percentile values are calculated from Triumph models in this specifications database. Always double-check important specifications against the motorcycle owner’s/service manual and official Triumph information before relying on them. Visit the official Triumph website.