| MODEL | LAMBRETTA 125B 1951 |
| Year | 1951 |
| Engine Type | Single cylinder, two-stroke |
| Displacement / Capacity | 123 cc / 7.51 cu in |
| Bore X Stroke | 52 x 58 mm / 2.0 x 2.3 in |
| Compression Ratio | 6.1:1 |
| Cooling System | Air |
| Max Power | 3.1 kW / 4.3 hp @ 4500 rpm |
| Max Torque | — |
| Ignition | Contact breaker and points |
| Induction | Carburettor, Dell'Orto MA 16 |
| Start System | — |
| TRANSMISSION SPECS | |
| Lubrication | 5% |
| Gear Box | 3-speed |
| Clutch | Hand changed |
| Final Drive | — |
| CHASSIS SPECS | |
| Frame | Tubular steel |
| Front Suspension | — |
| Rear Suspension | — |
| Front Brakes | Expanding (drum) |
| Rear Brakes | Expanding (drum) |
| DIMENSION SPECS | |
| Overall Length | — |
| Overall Width | — |
| Overall Height | — |
| Seat Height | — |
| Wheelbase | — |
| Ground Clearance | — |
| Dry Weight | 69.9 kg / 154 lb |
| Wet Weight | — |
| WHEEL SPECS | |
| Front Tyre | 4-8 |
| Rear Tyre | 4-8 |
| FUEL SYSTEM | |
| Fuel Capacity | — |
| Fuel Consumption | — |
| Top Speed | 67.6 km/h / 42 mph |
The 125B was an early Lambretta, a small two-stroke scooter with a tubular steel frame, a three-speed hand-operated gearchange and small 8-inch wheels. It was built in the first years of the marque as cheap, simple everyday transport.
