Yamaha SR400 (1978-80)

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The Yamaha SR400 motorcycle was produced between 1978 to 1980. It has a four-stroke, single cylinder, SOHC engine with a capacity of 399cc and a compression ratio of 8.5:1. It is air-cooled and has a dry sump lubrication system. The BSR33 carburetor provides induction, and the CDI provides ignition. The kick-start provides the bike’s starting mechanism. The maximum power it can generate is 27 hp at 7000 rpm, and its maximum torque is 27.4 Nm at 6500 rpm. The SR400 has a wet, multiple disc clutch and a 5-speed transmission system. The final drive is through a chain mechanism. The frame is made of steel double cradle with 35mm telescopic fork suspension at the front and dual shock, 5-way adjustable preload rear suspension. The front brakes consist of a single disc while the rear brake is a drum. Its front tyre is 3.50-19, and the rear tyre is 4.00-16. It has a rake caster angle of 27 degrees and a wheelbase of 1410mm. The wet weight of the bike is 174kg with a ground clearance of 130mm and a fuel capacity of 12 litres. The SR400 has a seat height of 790mm and a front wheel travel of 150mm while the rear wheel travel is 105mm.

Technical specifications:

Make Model: Yamaha SR 400

Year: 1978 – 80


Engine: Four stroke, single cylinder, SOHC, 2 valves per cylinder.
Capacity: 399 cc / 24.3 cu-in
Bore x Stroke: 87 67.2 mm
Compression Ratio: 8.5:1
Cooling System: Air cooled
Oil Capacity: 2.4 Litres
Lubrication: Dry sump
Induction: BSR33 carburetor
Ignition: CDI
Starting: Kick
Max Power: 27 hp / 17.1 KW @ 7000 rpm
Max Torque: 27.4 Nm / 6.3 kgf-m @ 6500 rpm
Clutch: Wet, Multiple Disc
Transmission: 5 Speed
Final Drive: Chain

Frame: Steel Double Cradle
Front Suspension: 35mm Telescopic fork
Front Wheel Travel: 150 mm / 5.9 in
Rear Suspension: Dual shocks, 5-way adjustable preload
Front Wheel Travel: 105 mm / 4.1 in
Front Brakes: Single disc
Rear Brakes: Drum
Front Tyre: 3.50-19
Rear Tyre: 4.00-16
Rake Caster Angle: 27 o
Trail: 111 mm / 4.4 in
Wheelbase: 1410 mm / 55.5 IN
Seat Height: 790 mm / 30.9 in
Ground Clearance: 130 mm / 5.1 in
Wet Weight: 174 kg / 384 lbs
Fuel Capacity: 12 Litres / 3.2 gal

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