| MODEL | YAMAHA YZ490 1987 |
| Year | 1987 |
| Engine Type | Single cylinder, 2-stroke |
| Displacement / Capacity | 490 cc / 29.9 cu in |
| Bore X Stroke | — |
| Compression Ratio | — |
| Cooling System | Air cooled |
| Max Power | 40.1 kW / 55 hp @ 7000 rpm |
| Max Torque | — |
| Ignition | — |
| Induction | Carburettor |
| Start System | — |
| TRANSMISSION SPECS | |
| Lubrication | — |
| Gear Box | 5-speed |
| Clutch | Wet plate |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | Steel |
| Front Suspension | — |
| Rear Suspension | — |
| Front Brakes | Single disc |
| Rear Brakes | Drum (expanding) |
| DIMENSION SPECS | |
| Overall Length | — |
| Overall Width | — |
| Overall Height | — |
| Seat Height | — |
| Wheelbase | — |
| Ground Clearance | — |
| Dry Weight | 107 kg / 236 lb |
| Wet Weight | — |
| WHEEL SPECS | |
| Front Tyre | — |
| Rear Tyre | — |
| FUEL SYSTEM | |
| Fuel Capacity | — |
| Fuel Consumption | — |
| Top Speed | — |
The YZ490 was Yamaha's biggest two-stroke motocross bike of the late 1980s, a 490 cc single built for open-class racing. The 1987 version was an air-cooled, five-speed machine with a drum rear brake, with a steel frame and a dry weight of about 107 kg.
