Yamaha’s classic air-cooled twin!

The RD400 was a last hurrah for the 1970s. The RD400 held sway in the middle ground of the middleweights, but its days were numbered; come June 1980 the RD350LC would kill it stone dead.

But in 1979 this was the bike every young motorcycle-mad Brit male hankered for. Those Yamaha US colours, the yellow/black/white speed block, spoke of TZ on-track superiority.

Being air-cooled, not cloaked in a water-jacket you just hear it, feel it more. Rev it and the RD gets louder, the baffles rattle and the cylinder fins vibrate, almost making the air shake. Then there’s that blue haze of unburned hydrocarbons… hmmm!

Saddle up and kick off and you’ll find that this RD – like many twostroke road bikes – is, in fact, far more flexible and easier to ride than even mid-sized four-strokes. That all changes as the revs come up, and approaching 6000rpm the RD comes on pipe in a fairly determined manner. It pulls strong, there’s a distinct mid-range hit – but those reed-valves that debuted with the RD range (in 1973) certainly make for a broad controllable hit of power.

The RD400 is a true classic, helped by having been so dominant for half a decade, but also by today being an all-round nice ride: best examples can cost around £6000… But, the RD is easy to live with and to work on, while being comfortable and a little sporty when it comes to the riding. Heavier than it needed to be, slower than it could have been, yet somehow still a gem of a middleweight.