Yamaha xs400 (1979)

The Yamaha XS 400 is a motorcycle with a four-stroke, 180 degrees parallel twin engine, SOHC, 2 valves per cylinder, and a capacity of 392 cc / 23.9 cu-in. It has a bore x stroke of 69.0 x 52.4 mm, and an air-cooled cooling system with a compression ratio of 9.2:1.

The XS 400 has pressure-lubricated wet sump lubrication, and its induction is 2x Mikuni BS32 carburettors with battery ignition and contact breaker points for the ignition system. It has both electric and kick starting options.

The motorcycle has a maximum power of 36 hp / 26.8 kW at 8100 rpm and a maximum torque of 3.3 kgf-m / 23.8 lb-ft at 8000 rpm. Its clutch is wet multiplate with a six-speed transmission and a chain final drive.

The XS 400 has a tubular steel, semi-double cradle frame and a telescopic fork front suspension, with dual shocks swing arm, preload adjustable rear suspension. The motorcycle has a single disc front brake, a drum rear brake, and a front and rear tyre size of 3.00-18 and 3.50-18, respectively.

The XS 400 has a wheelbase of 1364 mm / 53.7 in, a seat height of 780 mm / 30.7 in, a wet weight of 182 kg / 401 lbs, and a fuel capacity of 14 litres / 3.7 US gal.


Technical specifications:

Make Model: Yamaha XS 400

Year: 1979 –


Engine: Four stroke, 180 degrees parallel twin, SOHC, 2 valves per cylinder
Capacity: 392 cc / 23.9 cu-in
Bore x Stroke: 69.0 x 52.4 mm
Cooling System: Air cooled
Compression Ratio: 9.2:1
Lubrication: Pressure-lubricated wet sump
Induction: 2x Mikuni BS32 carburetors
Ignition: Battery ignition – With contact breaker points
Starting: Electric & kick
Max Power: 36 hp / 26.8 kW @ 8100 rpm
Max Torque: 3.3 kgf-m / 23.8 lb-ft @ 8000 rpm
Clutch: Wet multiplate
Transmission: 6 Speed
Final Drive: Chain
Frame: Tubular steel, semi-double cradle

Front Suspension: Telescopic fork
Rear Suspension: Dual shocks swing arm, preload adjustable
Front Brakes: Single disc
Rear Brakes: Drum
Front Tyre: 3.00-18
Rear Tyre: 3.50-18
Wheelbase: 1364 mm / 53.7 in
Seat Height: 780 mm / 30.7 in
Wet Weight: 182 kg / 401 lbs
Fuel Capacity: 14 Litres / 3.7 US gal

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