HONDA
TURBO
The
CX500 Turbo with which Honda stunned the motorcycle world in 1982 was
one of the least likely bikes ever to be put into production. The
turbocharged V-twin was large, heavy, complex and expensive. From the
moment it was unveiled, many observers regarded the Turbo as more of
a corporate statement than a serious superbike.
Honda's
ostentatious V-twin was the first of the string of turbocharged
machines that would see all of the big four Japanese manufacturers
try their luck with forced induction. The Honda was the most curious
in its choice of powerplant. Turbochargers, which use exhaust gas to
compress the intake charge, are best suited to large engines that
operate at a steady load; the opposite of a motorcycle's situation.
In addition, multi-cylinder motors help by smoothing the exhaust
flow.
Despite
this, Honda selected their middleweight CX500, an 80-degree
transverse V-twin with pushrod
valve operation. The CX's small cylinders required the world's
tiniest turbocharger, which was built by IHI to Honda's
specification. Its rotors measured less than two inches (51mm) in
diameter and were designed to spin at 200,000rpm.
HONDA
TURBO
Strengthened
engine
The
CX's crankcases were strong enough to be retained, but much of
liquid-cooled engine was uprated. A stronger crankshaft, clutch and
conrods, plus Honda's first production-specification forged pistons,
all helped to keep it together when the turbo increased peak power
from the standard CX500's 50bhp to the Turbo's 82bhp at SOOOrpm.
Honda's
work by no means ended with the powerplant. The CX was a rolling
showcase for other technical achievements, including its digital
ignition and fuel-injection system, Pro-Link rear suspension, TRAC
anti-dive, twin-piston brake calipers and redesigned Comstar wheels.
In addition the fairing, with its lipped screen, enormous headlamp
and integral indicators, was undeniably stylish. It held a
sophisticated instrument console that contained a clock and fuel
gauge, as well as the turbo boost gauge.
The
fairing worked well, too, allowing highspeed cruising in
comfort. The CX also handled very well considering its fuelled-up
weight of over 5501b (250kg). But for such a big, expensive bike the
Turbo was only moderately fast. It was good for 125mph (201km/h) but
its acceleration was marred by all that weight. And the engine also
suffered from turbo-lag, the intrusive delay between throttle opening
and engine response which made precise ,throttle control difficult.
For
long-distance riding at speed the Turbo was impressive even so, but
it was not so outstanding that its weight, complexity and expense
were overcome. A year later, in 1983, Honda followed it with the
CX650 Turbo, which had less lag plus a substantial power increase
that gave thrilling acceleration and a top speed of 135mph (217km/h).
The bigger model was an even better grand tourer. But it was still
not a sales success against simpler, cheaper rivals, and remained in
production for only a year.
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