The Yamaha SR400 was a single cylinder, four-stroke Naked motorcycle produced by Yamaha between 1978 and 2019. Max torque was 20.21 ft/lbs (27.4 Nm) @ 3000 RPM. Claimed horsepower was 22.4 HP (16.7 KW) @ 6500 RPM.
Manufacturer | Yamaha |
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Also called | SR400 WrenchMonkees GibbonSlap, SR400 35-years, SR 400 35-years, SR400 B.S.R, SR400 Stallion and Bronco, SR400 Lightening by Deus, SR400 Homage by Benders, SR400 Gibbonslap, SR400 Yard Built by Krugger, SR 400 |
Production | 1978 - 2019 |
Class | Naked |
Engine | single cylinder, four-stroke |
Bore / Stroke | 87.0mm x 62.7mm |
Compression ratio | 8.5:1 |
Horse Power | 22.4 HP (16.7 KW) @ 6500RPM |
Torque | 20.21 ft/lbs (27.4 Nm) @ 3000RPM |
Ignition type | tci: transistor controlled ignition |
Battery | 8.5:1 |
Transmission | Gear box: 5-speed Final Drive: chain |
Suspension | Front: telescopic Rear: swdual shock swingarm |
Brakes | Front: single disc. hydraulic. Rear: expanding brake (drum brake) |
Front Tire | 90/100-18 |
Rear Tire | 110/90-18 |
Wheelbase | 55.51 inches (1410 mm) |
Dimensions | L 82.09 inches (2085 mm) W 29.53 inches (750 mm) H 43.11 inches (1095 mm) |
Seat height | 30.91 inches (785 mm) |
Weight | 335.1 pounds (152.0 Kg) (dry), 174.0 kg (wet) |
Fuel capacity | 3.17 Gallon (12.00 Liters) |
Oil capacity | 0.63 Gallon (2.40 Liters) |
Fuel consumption | 3.56 liters/100 km (28.1 km/l or 66.07 mpg) |
Manuals | Service Manual |
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Engine
The engine was a air cooled single cylinder, four-stroke. A 87.0mm bore x 62.7mm stroke result in a displacement of just 399.0 cubic centimeters. Fuel was supplied via a single overhead cams (sohc).
Drive
The bike has a 5-speed transmission. Power was moderated via the wet, multiple disc.
Chassis
It came with a 90/100-18 front tire and a 110/90-18 rear tire. Stopping was achieved via single disc. hydraulic. in the front and a expanding brake (drum brake) in the rear. The front suspension was a telescopic while the rear was equipped with a swdual shock swingarm. The SR400 was fitted with a 3.17 Gallon (12.00 Liters) fuel tank. The bike weighed just 335.1 pounds (152.0 Kg). The wheelbase was 55.51 inches (1410 mm) long.
1978 - 2002 Yamaha SR 400
The road sport models SR400 and SR500 were released in 1978, following in the steps of the XT500 which had the same single cylinder engine.
2002 - 2006 Yamaha SR 400
The 2002 SR 400 has a lower displacement, achieved with a different crankshaft and shorter piston stroke. The SR 400 was produced until 2008 and then reintroduced in 2010 with a fuel injection system in place of the 'old' carburetor.
2011 Yamaha SR 400
For 2010 Yamaha has replaced the carburetor with a fuel injection, a new exhaust with a catalyser and a new sensor bigger than before, and a fuel pump is required to pressurise the injector.
2012 - 2016 Yamaha SR 400
The 2012 Yamaha SR 400 is powered by a 399 cc, single-cylinder, air-cooled, SOHC, 2-valve engine that produces a torquey, “thumper” engine character that makes it an absolute blast to ride. Fuel injection gives the motor fantastic response and modern practicality.