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 SR400 - £3780
Engine: 399cc, air-cooled 2v OHC four-stroke single. Five gears
Torque: 20 lb-ft
Seat height: 790mm
Fuel capacity: 12 litres