Positioned in Yamaha's naked motorcycle lineup, the 1981 Yamaha XJ 400 Seca utilizes a 398 cc (24.3 cu in) air-cooled four cylinder boxer, four-stroke layout. In factory specification, peak output is rated at 45 HP (32.8 kW) at 10,000 rpm while maximum torque reaches 33.9 Nm (25 lb-ft) at 8,000 rpm, transferring power to the rear wheel through a 6-speed gearbox and chain final drive. With a specific output of 113.1 HP per liter and a 2,000 rpm working window between peak torque (8,000 rpm) and peak power (10,000 rpm), the engine character is reflecting a performance-oriented street tune that balances strong mid-range pull with an energetic top-end rush.
On the scales, the XJ 400 Seca measures 176 kg (388 lbs) dry, translating to a power-to-weight ratio of 0.26 HP/kg (3.91 kg per horsepower).
Specific Output
113.1 HP/L
Power-to-Weight
0.26 HP/kg (3.91 kg/HP)
Power Band Window
8,000–10,000 rpm
Engine
Displacement398.0 ccm (24.29 cubic inches)
Engine TypeFour cylinder boxer, four-stroke
Engine DetailsFour cylinder boxer, four-stroke
Power45.0 HP (32.8 kW)) @ 10000 RPM
Torque33.9 Nm (3.5 kgf-m or 25.0 ft.lbs) @ 8000 RPM
Use this page to compare this motorcycle by its real specifications, not only by model name. Focus on the details that affect fit, comfort, handling, range and ownership.
Power
Compare engine output with similar motorcycles if acceleration, highway use or two-up riding matters.
Torque
Torque is useful for judging real-world pull, especially for touring, commuting and loaded riding.
Weight
Compare weight carefully because it affects low-speed handling, parking and confidence.
Brakes
Brake setup is worth comparing if you ride in traffic, mountains or with a passenger.
Suspension
Suspension details can matter for comfort, road feel and long-distance riding.
Transmission
Transmission and final drive affect maintenance, smoothness and everyday usability.
