Yamaha's
two-stroke middleweight twins [ were among the outstanding bikes of
the 1970s, providing a combination of performance and value that made
them hugely popular. Best known were the RD350 and RD400 models but
it was with the earlier YR5 that the legend of Yamaha's giant-killing
350cc two-stroke screamers began.
The
initials RD stood for Race Developed, and that was very much true of
the YR5 too. Yamaha had already begun to dominate 250cc grand prix
racing when the YR5 was introduced in 1970. In that year Yamaha's TD2
air-cooled twin-cylinder production racer not only took British rider
Ron Gould to the world championship, but it also occupied the first
seven places. Much of the same technology
was used for the roadsters, which were also produced in 125, 200 and
250cc capacities.
Like
its smaller siblings, as well as predecessors dating back to the YR1
of 1967, the 347cc YR5 was based around a piston-ported two- stroke
twin with a 180-degree crankshaft arrangement. It breathed in through
a pair of 28mm Mikuni carbs, and out through a pair of horizontal
chromed pipes. The gearbox was a five-speeder, with a modern change
pattern that put neutral between first and second, instead of at the
bottom of the box like some rivals. Peak power was 36bhp at 7000rpm.
In
contrast to the off-road-influenced styling of its predecessors,
which had featured crossbar-style handlebars and high-level exhaust
systems, the YR5
was very much a roadster. Although its handlebars were still high,
the bike had sleek and simple styling, and was shorter, lower and
lighter at 3311b (150kg). Its frame was a twin-downtube steel
structure, reinforced at the steering head and swingarm pivot with
the benefit of Yamaha's grand prix racing experience.
YAMAHA 350
YAMAHA 350
Noise,
smoke and acceleration
That
racing heritage was clear on the road, where YR5 riders required
little imagination to see themselves in the saddle of a high-revving
grand prix racer. The Yamaha two-stroke burbled, rattled and smoked
(when cold) like a true two-stroke, albeit a sophisticated and
well-behaved one. More importantly it had thrilling acceleration,
revved to 8000rpm through the gears, cruised smoothly at an indicated
80mph (129km/h) and reached a top speed of 95mph (153km/h).
Handling
was pretty good, thanks to the rigid frame ,light weight and simple
but reasonably well- controlled suspension.
Cycle World
described the YR5 its a quick-handling machine, with 'little to
inhibit the rider from pitching the machine aggressively through his
favourite set of bends. Damping seems quite up to par, and the tyres
deliver good tracking precision and traction." The Yamaha's
front and rear drum brakes were progressive, grab-free and with only
a slight tendency to fade under repeated use.
The YR5's
blend of good looks, reliability, lively performance and competitive
price quickly made it popular on both sides of the Atlantic. For the
next few years Yamaha's two-stroke twins would be hugely successful
in the showrooms, just as they were on the racetrack. The old adage
that 'racing improves the breed' was never more brilliantly proven.
YAMAHA 350 prices 2014
MINT $4,500 $5,500 £3.000 £4,000
GOOD $2.800 £2,500
FAIR $1.750 £1,250
PROJECT $900 £750
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