Reprinted from Cycle Guide, September, 1981
12 TURBO MOTORCYCLE INTERNATIONAL OWNERS ASSOCIATION " FALL 1998
even that figure doesn t seem unreasonable for
a machine chock-full of enough fresh thinking
and electrifying performance to affect the wow
and flutter of motorcycling for a long, long
time.
You shouldn t have to do more than just look
at the thing, though, to get your first clues as
to what makes the motorcycle so important.
The graceful lines of the integrated full fairing,
the tidy cockpit with its elaborate instrumenta-
tion under glass, the consistency and continu-
ity of the graphics every element combines to
effect one of the most visually striking motor-
cycles ever built. And that feeling was shared
by just about everyone who laid eyes on the
Turbo. Yet despite being almost revolutionary in
nature, the styling still seems evolutionary,
retaining classic motorcycle shapes and propor-
tions. Clearly, there is much for moto-designers
around the world to learn from this styling
exercise.
Too, the CX Turbo has the enviable distinc-
tion of being the very first turbo charged
motorcycle to be built that way on a produc-
tion-line basis. Granted, Kawasaki offered a so-
called  stock turbobike, the Z1-R TC, a few
years back; but it was nothing more, really,
than a bike that had rolled off the assembly
line in Japan in a normally-aspirated state
By Paul Dean
Photos by Chris Eastman and David Dewhurst
t was billed as Honda s message from the
future, an experimental ideabike put on exhi-
Ibition to give today s riders a sneak preview of
tomorrow s motorcycles.
If that s true, then it would seem that Honda
Motor Company s definition of a futurebike is one
that s just on the verge of rolling off the assembly
line. Because less than a year after its unveiling as
a supposed blueprint for things to come, Honda s
CX500 Turbo  the turbocharged, fuel-injected
and outrageously stylish dreambike you first saw
in the January 1981 issue of Cycle Guide  is no
longer an engineering showpiece on display in
some motorized tomorrowland; it is present-day
fact, a limited-production reality that soon will be
on sale in Honda showrooms everywhere. And we re
here to tell you, after testing four pre-production
prototypes, that not only is the Turbo one of the
most exciting-looking motorcycles in recent histo-
ry, it s one of the most thrilling to ride, as well.
Honda has not yet disclosed exactly how many
copies of this fantasy-come-true will be built or
how much each one will cost; but our contacts at
the company are guessing that about 2000 will hit
these shores this year, and that the suggested ask-
ing price could soar to $5000-plus. But some how,
TURBO MOTORCYCLE INTERNATIONAL OWNERS ASSOCIATION " FALL 1998 13
before being fitted with an aftermarket turbo kit here in the slows down so much that it does not produce any boost in
U.S. Not so the CX500 Turbo, which was conceived and engi- the intake tract. And even when the throttle is turned wide-
neered from Day One to be turbocharged and not as simply open the engine doesn t respond crisply at first because it
a standard-issue CX500 with a turbo system dropped in place, takes a short while for the increased flow of exhaust gases to
but as a complete and original turbobike concept. get the turbo spinning again at boost-producing rpm.
Indeed, that total orchestration is evident in virtually every Turbo lag is the most infamous of the drawbacks inherent
aspect of the CX-T. Whether it s the bike s visual impact, its in turboed engines, especially, those of smallish displacement.
mechanical sophistication or the acceleration it can unleash And for Honda to make headway in that area involved noth-
any time it is  on the boost, to use the proper turbo-par- ing less than the development of in conjunction with IHI, a
lance, this motorcycle sets standards that other manufacturers Japanese company with great expertise in the turbo field the
will be hard-pressed to even equal, let alone surpass. And the world s smallest turbocharger unit. It also entailed the careful
high caliber of execution that s apparent in some of the design and placement of two different plenum-type chambers
Turbo s support systems could have significant long-term in the intake tract. This novel approach acts to damp the
effects on the entire motorcycle industry. uneven intake pulses that result from the CX s vee-twin
For instance, in working to overcome the problems that engine configuration, for those irregularities could cause the
seem always to have bothered aftermarket turbo installations, turbo to have a different rotational speed during one cylin-
Honda actually advanced world technologies in several areas. der s intake cycle than during the other s. And original solu-
One of them, of course, is the turbo system itself, which was tions to other commonplace turbo-system problems can be
expressly designed to eliminate or at least minimize  turbo found in the CX-T s electronic fuel injection and solid-state
lag. That s the term commonly used to describe what hap- ignition, both of which are interconnected and controlled by
pens when a turbocharged engine makes the transition from motorcycling s first digital (rather than analog), self-analyz-
closed throttle to open (usually wide open) throttle. Since the ing computer.
heat and volume of the exhaust gases is diminished when the There s more to be read about these and other turbo-related
throttle is in the closed position, the spinning turbo wheel innovations on the CX Turbo in  The Taming Of Turbo on
14 TURBO MOTORCYCLE INTERNATIONAL OWNERS ASSOCIATION " FALL 1998
A vee-six Turbo freight train makes a singular
sound as it hauls through the hills
things really start to happen in a hurry. You begin to hear
and to feel the rapidly growing intensity of each power
impulse as the boost pressure quickly builds, and by 4000 or
4500 rpm you re being launched down the blacktop with a
ferocity that seems almost impossible from a 497cc, 549-
pound motorcycle.
Of course, the duration of this transition from off the boost
to on it, and the resultant acceleration, as well, depends on
what gear the Turbo s five-speed transmission is in. In first,
the whole sequence of events happens so quickly that it s
easy enough to accidentally overrev past the nine-grand red-
line, especially the first couple of times you try a full-throttle
run. In second and third, the transition is more gradual and a
lot easier to observe, but the acceleration between 4000-9000
rpm still is so god awfully vicious that it slides you back on
page 22. The bottom line for right now, though, is that out
on the road, the finished product seems to work far better
than any turbocharged motorcycle we ve ever ridden.
It doesn t seem that way at first, since anywhere below
about 3500 rpm the engine responds like a slightly detuned
standard CX500 which, in fact, it really is, what with a
lower compression ratio, smaller exhaust valves and milder
cam timing, all in accordance with proven turbo and super-
charging tuning practices. But by the time the tach needle
swings past the 3500-rev mark with the throttle wide-open,
TURBO MOTORCYCLE INTERNATIONAL OWNERS ASSOCIATION " FALL 1998 15
the mildly notched seat and pulls your arms straight like some
Nautilus exercise machine gone mad. Naturally, in fourth and
fifth the transition is slower yet, and dialing the throttle wide-
open even at 4000 rpm is not answered with a breathtaking
luge forward turbo lag, if you will. But once the boost kicks
in, all 19 pounds of it, the acceleration in those two top gears
isn t all that much weaker than in second and third.
Unfortunately, we weren t able to quantify the Turbo s perfor-
mance potential in our usual fashion. That was because the four
bikes we tested were late-stage prototypes for which no spare
parts were immediately available, and Honda therefore wouldn t
allow us to subject them to the rigors of dragstrip or
dynamometer testing. So the next best thing available to US
during our abbreviated evaluation was to do a series of roll-on
acceleration comparisons with a Honda CB900F that was along
on the ride. And that, with the help of the butt-mounted dyno
that each of us has developed over the years, told us just about
everything we needed to know about the engine s performance,
thank you.
In a top-gear roll-on from 50 mph, for instance, the Turbo
bolted away from the 900 as though the rider on the CB had
accidentally hit the brakes. What s more, the 900 could barely
keep up with the CX if the roll-on was conducted with the
Turbo in fifth and the CB in fourth. And if the CX was  pre-
boosted (the practice of maintaining the bike s static speed
with the rear brake while the throttle is held wide-open, and
when full boost is reached, which takes just a few seconds, usu-
ally, the brake is released and maximum acceleration begins
immediatey) before the roll on was begun, the 900 had to he
down shifted all the way to third gear before it
could run with the Turbo which was still in fifth!
16 TURBO MOTORCYCLE INTERNATIONAL OWNERS ASSOCIATION " FALL 1998