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Yamaha SR 400SP

Make Model	Yamaha SR 400SP
Year	1983
Engine	Four stroke, single cylinder, SOHC, 2 valves per cylinder.
Capacity	399 cc / 24.3 cu-in
Bore x Stroke	87 х 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	27º
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

The first incarnation of the SR since 1978, when it was introduced to the market SR500 (which was then presented as a more road-oriented use of the legendary XT500, launched just three years earlier), but at that time the model received a great success due to the advent of fractional motors, which made it look immediately 'dated' his single cylinder 499 cc. Initially marketed in several markets, the SR in recent years has been offered almost exclusively in Japan only as SR400,

with a shorter stroke so you can take advantage of the laws of the country of the Rising Sun that require a certain license for motorcycles up to 400 cc displacement. The SR400 was produced until 2008 and then reintroduced in 2010 with a fuel injection system in place of the 'old' carburetor.

The SR400 engine has a lower displacement, achieved with a different crankshaft and shorter piston stroke[4][5] and both models feature only kickstarting, i.e., no electric starter.

The SR400 has been marketed in the Japanese Domestic Market (JDM) since 1978 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",[6] 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.[6]

The SR was styled by Atsushi Ishiyama with Yamaha presenting a pre-production prototype to US dealers in late 1975.[6] Ishiyma 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.