Yamaha xs400 (1977-78)

The Yamaha XS 400 was a motorcycle produced in 1977-78. It had a four-stroke 180-degree parallel twin engine with a capacity of 392 cc and was air-cooled. The bike had two valves per cylinder and a compression ratio of 9.2:1. The XS 400 had a pressure-lubricated wet sump lubrication system, 2x Mikuni BS32 carburetors for induction, and electric and kick starting options. The bike had a maximum power output of 36 hp at 8100 rpm and maximum torque of 3.3 kgf-m at 8000 rpm. It had a wet multi-plate clutch and a 6-speed transmission, and its final drive was through a chain. The XS 400’s frame was made of tubular steel and was a semi-double cradle. It used a telescopic fork for front suspension and dual shocks swing arm for rear suspension. Its front brake was a single disc, and rear brake was a drum. The bike’s wheelbase was 1364 mm and its seat height was 780 mm. The XS 400 weighed 182 kg and had a fuel capacity of 14 litres.

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Technical specifications:

Make Model: Yamaha XS 400

Year: 1977 – 78

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