1979 Yamaha XS 400 specifications

Available technical data for this model and year. Specifications can vary by market and version.

Technical specifications

Displacement	392.0 ccm (23.92 cubic inches)
Engine type	Twin, four-stroke
Power	27.0 HP (19.7 kW )) @ 7000 RPM
Torque	31.2 Nm (3.2 kgf-m or 23.0 ft.lbs) @ 6000 RPM
Compression	9.2:1
Bore x stroke	69.0 x 52.4 mm (2.7 x 2.1 inches)
Valves per cylinder	2
Fuel system	Injection. 2 x Mikuni BS32
Fuel control	Overhead Cams (OHC)
Ignition	Battery ignition - With contact breaker points
Cooling system	Air
Gearbox	6-speed
Transmission type	Chain (final drive)
Clutch	Wet multiplate
Front suspension	Telescopic fork
Rear suspension	Dual shocks swing arm, preload adjustable
Front brakes	Single disc
Rear brakes	Expanding brake
Front tyre	3.00-18
Rear tyre	3.50-18
Dry weight	182.0 kg (401.2 pounds)
Weight incl. oil, gas, etc	182.0 kg (401.2 pounds)
Seat height	780 mm (30.7 inches) If adjustable, lowest setting.
Wheelbase	1364 mm (53.7 inches)
Fuel capacity	17.00 litres (4.49 US gallons)
Top speed	140.0 km/h (87.0 mph)

Source: Bikez: XS 400, 1979. Retrieved 2026-09-19. Match confidence: exact.

Years listed are the entries held in this archive, rather than a complete production history.