Yamaha SR400 & SR500
Yamaha SR400 at the 2009 Tokyo Motor Show | |
| Manufacturer | Yamaha Motor Company |
|---|---|
| Parent company | Yamaha Corporation |
| Production | 1978−2021 |
| Assembly | Japan: Iwata, Shizuoka |
| Class | Standard |
| Engine | 499 cc (30.5 cu in) 4-stroke, air-cooled, SOHC, single-cylinder, 2-valve |
| Bore / stroke | 87 mm × 84 mm (3.4 in × 3.3 in) |
| Compression ratio | 9.0:1 |
| Top speed | SR500: 146 km/h (91 mph) |
| Power | SR500: 23.5 kW (31.5 hp) @ 6,500 rpm |
| Torque | SR500: 36.3 N⋅m (26.8 lbf⋅ft) @ 5,500 rpm |
| Ignition type | CDI |
| Transmission | 5-speed sequential manual |
| Frame type | Half-duplex cradle |
| Suspension | Front: 35 mm telescoping fork, 150 mm (5.9 in) travel Rear: 105 mm (4.1 in) travel, 5-way adjustable preload |
| Brakes | Hydraulic disc or mechanical drum, depending on model year |
| Tires | F: 3.50-19 or 3.50-18 R: 4.00-18 |
| Rake, trail | 27.5 deg, 117 mm (4.6 in) |
| Wheelbase | 1,405 mm (55.3 in) |
| Dimensions | L: 2,105 mm (82.9 in) W: 845 mm (33.3 in) H: 1,155 mm (45.5 in) |
| Seat height | 810 mm (32 in) |
| Weight | SR500: 158 kg (348 lb) (dry) |
| Fuel capacity | 12 or 14 litres (2.6 or 3.1 imperial gallons; 3.2 or 3.7 US gallons) |
| Oil capacity | 2.4 litres (2.5 US quarts) |
| Fuel consumption | 4.8 L/100 km (59 mpg‑imp; 49 mpg‑US) |
The Yamaha SR400 (1978–2021) and SR500 (1978–1999) are single-cylinder, air-cooled, two-passenger motorcycles manufactured in Japan by Yamaha Motor Company as a street version of the Yamaha XT500, with a standard riding posture and styling recalling the Universal Japanese Motorcycles of the 1970s. The two models differ by their engines: the SR400 engine has a lower displacement, achieved with a different crankshaft and shorter piston stroke and both models feature only kickstarting, i.e., no electric starter.
The SR400 had been marketed in the Japanese Domestic Market (JDM) from 1978 to 2021 and was introduced to Europe, the Americas and Oceania in 2014. Its engine capacity complies with JDM 400 cc licensing restrictions.
The SR500 was marketed in Asia and Oceania (1978–1999), North America (1978–1981); and Europe (1978–1983), and was not marketed in the Japanese market.
The SR was originally developed under the design credo "easy to use", and when Yamaha's Technical Director wrenched his ankle while testing a prototype, easier starting became a priority—and Yamaha developed a decompression lever and sight glass system.
The SR was styled by Atsushi Ishiyama with Yamaha presenting a pre-production prototype to US dealers in late 1975. Ishiyama said of the bike's styling: "Our choice was to design the new SR500 with a strong family image and a strong link to our first four stroke, the XS 650 twin, which was also inspired by British design."