| MODEL | YAMAHA XJ 550 1981 |
| Year | 1981 |
| Engine Type | Four stroke, transverse four cylinder, DOHC, 2 valves per cylinder |
| Displacement / Capacity | 528 cc / 32.2 cu in |
| Bore X Stroke | 57 x 51.8 mm |
| Compression Ratio | 9.5:1 |
| Cooling System | Air cooled |
| Max Power | 37 kW / 50 PS @ 9000 rpm |
| Max Torque | 41.9 Nm / 4.3 kgf-m @ 7500 rpm |
| Ignition | Battery powered inductive |
| Induction | 4x 28 mm Mikuni carburettors |
| Start System | Electric |
| TRANSMISSION SPECS | |
| Lubrication | — |
| Gear Box | 6 Speed |
| Clutch | — |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | — |
| Front Suspension | Telescopic coil spring forks, 137 mm / 5.3 in travel |
| Rear Suspension | Swinging arm with dual dampers adjustable for preload, 80 mm / 3.7 in travel |
| Front Brakes | 2x 267 mm discs |
| Rear Brakes | 182 mm drum |
| DIMENSION SPECS | |
| Overall Length | — |
| Overall Width | — |
| Overall Height | — |
| Seat Height | — |
| Wheelbase | — |
| Ground Clearance | — |
| Dry Weight | — |
| Wet Weight | 205 kg / 450 lbs |
| WHEEL SPECS | |
| Front Tyre | 3.25-19 |
| Rear Tyre | 110/90-16 |
| FUEL SYSTEM | |
| Fuel Capacity | 15 Litres / 3.9 US gal |
| Fuel Consumption | 55 mpg (average) |
| Top Speed | 178.6 km/h / 111 mph |
The XJ550 brought Yamaha's transverse air-cooled four into the 550 class in 1981, positioned as a light, quick middleweight alternative to the 750s. Its Induction Control System was meant to improve combustion and fuel economy, and the road test praised handling and brakes but not the standard tyres and shocks.
