The Yamaha XJ 400 Seca motorcycle specifications include a 398 cc (24.29 cu in) engine, power of 45 hp (32.8 kW) @ 10,000 rpm, a 6-speed gearbox, and a listed weight of 176 kg (388 lb).
Key specifications
1981Year released
398 ccDisplacement
45 hpPower
33.9 Nm @ 8,000 rpmTorque
176 kgDry weight
How the Yamaha XJ 400 Seca compares
This compares the motorcycle with all Yamaha models in this specifications database. The blue marker is this model and the grey line is the Yamaha database average.
Engine power45 hp
Low 2.8 hpAverage 53.3 hpHigh 171.2 hp
About 16% lower than the Yamaha database average. Around the 53rd percentile across Yamaha models.
Displacement398 cc
Low 49 ccAverage 550 ccHigh 1,852 cc
About 28% lower than the Yamaha database average. Around the 46th percentile across Yamaha models.
This model Yamaha database average
Yamaha database percentile rankings
Percentiles show where this motorcycle sits across the Yamaha specifications database. They are descriptive database rankings, not performance ratings.
Engine power53rd
45 hp — more powerful than about 53% of Yamaha models with power data.
Displacement46th
398 cc — larger displacement than about 46% of Yamaha models.
Mechanical overview
Engine layout snapshot
Four cylinder boxer, four-stroke • 398 cc • Air cooled • 45 hp
Chassis snapshot
6-speed • Chain (final drive) • 2.50-19 front / 110/90-18 rear
Additional useful specifications
| Front tire size |
2.50-19 |
| Rear tire size |
110/90-18 |
| Rear tire width |
110 mm |
| Rear tire aspect ratio |
90% |
| Rear rim diameter |
18 in |
| Power-to-weight ratio |
0.256 hp/kg |
| Power-to-weight |
255.7 hp/tonne |
| Specific power |
113.1 hp/L |
| Bore/stroke ratio |
1.05:1 (Oversquare) |
Model information
| Year released |
1981 |
| Category |
Naked bike |
Engine specifications
| Engine type |
Four cylinder boxer, four-stroke |
| Displacement |
398 cc (24.29 cu in) |
| Power |
45 hp (32.8 kW) @ 10,000 rpm |
| Torque |
33.9 Nm (3.5 kgf-m or 25.0 ft.lbs) @ 8,000 rpm |
| Bore × stroke |
51.0 x 48.8 mm (2.0 x 1.9 inches) |
| Compression ratio |
9.7:1 |
| Cooling system |
Air |
| Fuel system |
Carburettor. 2×34 Mikuni |
| Fuel control |
Double Overhead Cams/Twin Cam (DOHC) |
| Ignition |
Battery Powered Inductive |
| Starter |
Electric |
Transmission and drivetrain
| Gearbox |
6-speed |
| Final drive |
Chain (final drive) |
Chassis and suspension
| Front suspension |
35mm Telescopic Forks |
| Rear suspension |
Single Adjustable Spring Preload |
| Front wheel travel |
142 mm (5.6 inches) |
| Rear wheel travel |
96 mm (3.8 inches) |
Brakes, wheels and tires
| Front brakes |
Single disc. 1 Piston Caliper |
| Rear brakes |
Expanding brake (drum brake) |
| Front tire |
2.50-19 |
| Rear tire |
110/90-18 |
Dimensions and weight
| Dry weight |
176 kg (388 lb) |
Performance
| Top speed |
162.5 km/h (101.0 mph) |
| 1/4 mile |
14.00 seconds |
| Power/weight ratio |
0.2557 hp/kg |
Electrical and instruments
| Battery |
Powered Inductive |
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 Yamaha models in this specifications database. Always double-check important specifications against the motorcycle owner’s/service manual and official Yamaha information before relying on them. Visit the official Yamaha website.