| MODEL | YAMAHA YD-1 1957 |
| Year | 1957 |
| Engine Type | Two stroke, piston-port, parallel twin |
| Displacement / Capacity | 247 cc / 15.0 cu in |
| Bore X Stroke | 54 x 54 mm |
| Compression Ratio | — |
| Cooling System | Air cooled |
| Max Power | 14.5 hp @ 6000 rpm |
| Max Torque | 4.1 kg-m @ 5000 rpm |
| Ignition | — |
| Induction | Single carburetor |
| Start System | Kick |
| TRANSMISSION SPECS | |
| Lubrication | — |
| Gear Box | 5 speed |
| Clutch | — |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | Pressed steel |
| Front Suspension | Telescopic forks |
| Rear Suspension | Swingarm |
| Front Brakes | Drum |
| Rear Brakes | Drum |
| DIMENSION SPECS | |
| Overall Length | — |
| Overall Width | — |
| Overall Height | — |
| Seat Height | — |
| Wheelbase | — |
| Ground Clearance | — |
| Dry Weight | — |
| Wet Weight | 138 kg / 309 lbs |
| WHEEL SPECS | |
| Front Tyre | 2.50-16 |
| Rear Tyre | 2.50-16 |
| FUEL SYSTEM | |
| Fuel Capacity | — |
| Fuel Consumption | — |
| Top Speed | — |
Yamaha's second model after the YA-1, this 250 cc air-cooled two-stroke twin was patterned on the German Adler MB 250. It used a pressed-steel frame rather than Adler's cradle, though racing versions went back to a cradle, and it won places at the 1957 Asama endurance race.
