‘The speedo needle crept towards 140 km/h, the engine screamed, the scenery rushed by… and it was very easy to understand the phenomenal sales success of Yamaha’s air-cooled, two-stroke parallel twins’
Roland’s take on the younger sibling of the legendary RD 350
SIMPLY CATCHING SIGHT OF the very clean white-and-red RD250E had brought back a few memories, and starting the engine really transported me back in time. The Yamaha fired up first kick with that raucous, clattery, off-beat rakkatack-tack of an exhaust note from its twin pipes, along with a small cloud of two-stroke exhaust smoke that provided the perfect, atmosphere-enhancing (and polluting) accompaniment.
I’d been looking forward to riding the RD250E all morning, and now I was really hooked. It’s a long time now since the late 1970s, when there were so many of them on the roads. But even now there’s something about Yamaha’s coffin-tanked twin that seems to sum up all that was best and craziest about the days when, for teenage speed freaks on a provisional licence, a hot Japanese 250-cc two-stroke like this was the height of motorcycling performance.
Ten minutes later, its engine warmed and the road ahead clear, the Yamaha revved hard through the gears while I held its throttle wide open, slid back on the seat and crouched down to help make the high-handlebarred RD as aerodynamically efficient as possible. The speedo needle crept towards 140 km/h, the engine screamed, the scenery rushed by… and it was very easy to understand the phenomenal sales success of Yamaha’s air-cooled, two-stroke parallel twins.
This RD250E was registered in 1980, the year that the RD250LC and its 350-cc sibling were unveiled, beginning a new era for Yamaha’s twostroke roadsters. That was also the year King Kenny Roberts won his third straight 500-cc world championship, reinforcing the image of a two-stroke Yam with speed-block paint scheme as just about the fastest, snarliest thing on two wheels. (Ironically, Kork Ballington and Kawasaki had by this time taken over the 250-cc class.)
The story of Yamaha’s twins had begun a long way before that. This bike’s blood-line goes directly back to 1957 and the YD-2, Yamaha’s first air-cooled two-stroke twin, which was developed from the company’s very first motorcycle, the 125-cc single-cylinder YA-1 Red Dragonfly of two years earlier. A few years later came the YDS-2, a more powerful and sophisticated 250 twin that was unleashed on export markets worldwide in the early 1960s.
Yamaha’s reputation for fast and furious two-strokes was enhanced by the firm’s grand prix success, notably in the 250-cc class, where Phil Read won three world championships in the 1960s. The world titles kept coming into the ’70s, with Britain’s Rodney Gould, Phil Read again, flying Finn Jarno Saarinen, and Germany’s Dieter Braun continuing the run between 1970 and ’73. In that year Yamaha renamed its new roadster the RD250, the initials standing for Race Developed.
The first RD250A had the rounded petrol tank and drum front brake of its predecessors, but was powered by a revised engine with dimensions of 54 x 54 mm, instead of 56 x 50 mm. It was also more compact, produced a claimed 30 PS and had reed-valve induction for the first time. “Featuring every merit of Yamaha’s world GP proven technologies,” boasted the advertising blurb, with some justification. Curiously, the new six-speed gearbox’s top ratio was blanked off in some markets, including the UK. One magazine still quoted a top speed of 160 km/h, along with “shattering acceleration”.
The major development came in 1976 with the RD250C which, along with its RD400C sibling, introduced a new, more angular look, complete with cast wheels and single disc brake front and rear. The larger model’s engine was increased in capacity from the old RD350. Although the RD250C retained its capacity, changes including the use of 28-mm Mikuni carbs in place of the earlier 24-mm units increased peak output to 32 PS at 8,000 rpm. The 1979-model RD250E introduced electronic ignition plus a frame with revised foot-rest mounting, but in performance terms was essentially unchanged.
Which brings us to this very clean 250E, which ran superbly well, firing up easily, idling effortlessly, and taking very little time to remind me just why the RD250 had such a great reputation in its heyday, even if it was slightly overshadowed following the introduction of Suzuki’s slightly quicker GT250 X7 in 1978. The X7 was a significant 23 kg lighter
but the fact that the Yam — which shared its chassis with the 44-PS RD400 — was larger and more substantial arguably made it a better roadster. Especially if, like me, you’re a lot bigger and heavier than the average 17-year-old.
At 165 kg with a gallon of unleaded in that rectangular tank, the RD250E was still a very light and manoeuvrable machine, which was partly why those 32 horses were able to make it seem so satisfyingly quick. At low revs the reed-valve two-stroke ran cleanly and pulled well enough for easy acceleration in the lower gears, without the need for frantic revving when pulling away (unless, of course, your mates were lined up alongside you at the lights).
Then at just before 6,000 rpm the motor reached its power-band and came alive, sending the bike surging forward with enough enthusiasm to put a smile on my face — and, no doubt, an even bigger one on the spotty countenances of its youthful owners more than three decades ago. The exhaust note hardened to a pleasingly racy two-stroke cry — far too loud to be legal these days — and the speedo needle kept on moving as I flicked through the six-speed box, which shifted nicely although this bike’s lever was set slightly too high for my liking.
Mindful of this bike’s age, I backed off at an indicated 140 km/h, but an RD250 was good for an indicated 160 km/h when new, even if its true top speed — when magazines got round to actually measuring such
The RD250E was much in demand by bike thieves and many others in its heyday even if it was slightly overshadowed following the introduction of Suzuki’s slightly quicker GT250 X7 in 1978
data, rather than estimating — was less than spectacular, at about 150 km/h. Inevitably, the raised handlebars meant high-speed cruising soon became tiring, and prompted many owners to fit ace bars. The rubber-mounted foot-rests were further back than the previous model’s and, like the rubber-mounted pegs, did a good job of keeping the parallel twin’s vibration at bay.
The Yamaha’s extra weight compared to the Suzuki X7 might have been a handicap in the heat of production race battle, but the more substantial RD, which also had a longer wheelbase, was the more stable handling of the two. Its chassis was identical to that of the slightly wheelie-prone RD400, and the 250 benefited from the frame strength and geometry designed to contain the more powerful motor. Even at high speed, with the wind flapping at my jacket and jeans, the Yam always felt stable and well controlled.
It handled pretty well at lower speeds, too, just as I remember my old RD400C doing many years ago. The wide bars and narrow Dunlop K82 tyres gave plenty of agility, despite the 18-inch diameter of the neat, seven-spoke alloy wheels. This bike’s suspension seemed to have survived well (despite slightly pitted fork stanchions, one of its very few cosmetic blemishes), and the ride was reasonably firm, with none of the bouncy, under-damped feel I’d half expected.
The Dunlops had more than enough grip to use all the fairly generous ground clearance, too, and would doubtless have worked much better in the wet than the Yokohama rubber with which the RD was generally fitted when new. The original brakes were rated poor in the wet, too. This bike’s modern pads would doubtless have helped, but even in the dry its front brake was lacking in bite. Curiously, Yamaha had changed to a single-piston calliper from the earlier RD’s twin-piston design. Even the faster RD400E had only a single disc, though, and most riders were probably happy enough.
Most RD250E owners were pleased with the air-cooled twin’s performance and reliability, too, and with its general level of quality. By this time the neat and simple instrument console included a light for low two-stroke oil. Indicators were self-cancelling, a feature sadly lacking in most modern bikes. Ironically, this RD’s self-cancellers didn’t cancel, the bike’s only real fault. Interestingly, it had been wired up so the kill-switch was off when in its on position, and vice-versa: a neat move intended to trick an opportunist thief.
The RD250E was much in demand by bike thieves and many others in its heyday, but tightening emission legislation and the demand for more performance meant that its period of glory was brief. This bike’s replacement, the liquid-cooled RD250LC, arrived in 1981 with more power and sophistication, but lacking a little of its predecessor’s raw charm. As Yamaha’s final model in a line of air-cooled 250-cc twins stretching right back to the 1950s, the RD250E was a mighty good way to end the very distinguished line.
Single-piston caliper and a solid steel disk at both ends required some serious pressure to provide any real stopping power
Rear suspension comprises twin shockabsorbers with preload adjustability
Twin-pod clocks with tell-tale lights in between were the rage back in the day
Flat seat meant that you had to really hold on under hard acceleration
Yamaha’s air-cooled twostroke twins are legendary