2010 - 2011 Yamaha SR400

Make Model	Yamaha SR 400
Year	2010 - 11
Engine	Four stroke, single cylinder, SOHC, 2 valve
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	Wet sump
Induction	Fuel injection
Ignition	TCI
Starting	Kick
Max Power	22.93 hp / 16.7 KW @ 6500 rpm
Max Torque	27.4 Nm / 20.2 lb-ft @ 3000 rpm
Clutch	Wet, Multiple Disc
Transmission	5 Speed
Final Drive	Chain
Frame	Steel Double Cradle
Front Suspension	Telescopic fork
Front Wheel Travel	150 mm / 5.9 in
Rear Suspension	Dual shocks swingarm
Rear Wheel Travel	104 mm / 4.1 in
Front Brakes	298mm single disc
Rear Brakes	Drum
Wheels	Wire spoked
Front Tyre	90/100-18
Rear Tyre	110/90-18
Rake Caster Angle	27º
Trail	112 mm / 4.4 in
Dimensions	Length 2085 mm / 82.1 in Width 750 mm / 29.5 in Height 1095 mm / 43.1 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	12.1 Litres / 3.2 US gal

Auto-By magazine in Japan has tested the new fuel-injected Yamaha SR400 for MCN – revealing it has lost none of its charm.

To clean the SR400’s emission for 2010 up Yamaha has replaced the carburettor with a fuel injection. It’s not a simple job though – a new exhaust with a catalyser and lambda sensor is also new (it’s slightly bigger than before), and a fuel pump is required to pressurise the injector.

This created a problem – a bulky pump would affect the tank shape, so to get around it the fuel tank feeds fuel in to a small sub-tank under the left side panel (which is 10mm wider to cover it) containing the pump. An air-injection system is the final change to clean the exhaust gases up.

Riding the bike reveals that it’s much the same as before – the chassis might be 30 years old but at 174kg with a low, narrow seat and wide bars, it handles well. You can’t rush it – smooth corner entry and throttle opening to gently load the suspension is the key to preventing wobbles, but while it isn’t nimble it’s good fun to thread through a series of corners.

Peak torque is slightly lower, but the torque curve is fatter and more linear through the rest of the rev range, so it accelerates quicker with better throttle response, especially from 4000-5000rpm. The clutch has a lighter spring too, which makes life easier.

Sadly, it’s only sold in Japan. A real shame – as a cool, easy to ride retro commuter the SR could win a few fans in the UK.

Yamaha SR 400