A full engine, gearbox and chassis redesign came with the GSX-R750WR
including improved engine internals, revised gears and forks, stainless
steel header pipes and six-piston brakes. Weight was down to 199 kg - a
point where the 130 hp GSX-R1100 was some 8 years earlier! In another odd
move, power was down to 112 hp at 10,500 rpm. 6 piston brake calipers and
ultrawide 180/55ZR17 rear tyre graced the R that weighed in 9 kg dry lighter
than the 1993 production model. The same 1994 model continued to be
available in 1995.
Although standard production model, the GSX-R750SPR was designed to serve
also as the Superbike racing platform and boasted performance features
direct from the factory racing parts bin. Wide-mouthed TRM40 carburetor,
SCAI air intake system, 4-2-1 exhaust system with increased flow, special
6-speed close-ratio gearbox, magnesium engine covers, aluminium water pump,
thin-walled 43 mm inverted tube front fork, lighter and more rigid swing
arm.
Race Rocket, eh?" yapped the joker down at the moving-and-storage company where we took our spanking-new 1994 GSXR750 for its initial weigh-in.
"Faster 'n' hell and twice as dangerous," he chattered, completely ignorant of
the real significance of the much-changed vessel sitting upon the scales.
"Wouldn't be caught dead on one."
Now might be as good a time as any to fall upon your knees and thank whatever
god you answer to that you're not one of the uninitiated, like this guy. Be glad
that you're able to appreciate the finer points of the very latest GSXR750: six-piston brake calipers, thicker fork tubes, a radically braced
swingarm, new headlights housed in a narrower fairing even new engine mounts
where there weren't any before. Smarter folk might even suspect changes not
easily visible.
The unenlightened, though, have their purpose in life, too. Maybe the reason
we like such things as GSXR750s is because they separate us from true dolts.
While the typical pickup-truck poltroon might admire a more utilitarian
motorcycle, he of limited perception is able to immediately ascertain the essence of the GSXR: surface-to-surface, liquid-cooled, nerve-guided, fired-from-the-crotch
curve missile. Do not use while under the influence of drugs, alcohol or
feeble-mindedness.
We did get the information we came for. The new GSXR weighs precisely 506
pounds, gassed—a full 19 pounds less than the '93 machine. Having liquid-cooled
and revamped the GSXR750 last year, Suzuki's goal for '94 was to reduce weight.
Seems they did.
Low mass, remember, was what made the original GSXR so phenomenally
successful in the first place—well, that and hot-pit styling. Suzuki's 1986
GSXRs brought the beauty of leanness, the real racer's edge, to the street. Then
Suzuki seemed to lose sight of that goal. GSXRs porked out. They continued to be formidable
motorcycles, but not as formidable as they might have been. The advantage of a
750 compared with an open-class bike should be one of compactness, weight
and therefore handling; but with the advent of lighter machines with more
displacement—Honda's CBR900RR—Suzuki suddenly realized it was being beaten at its own low-mass game.
As the Japanese submariner said while attempting to stuff a really big radio
down the hatch of his vessel in the John Belushi classic, "1941": "We got to
figure out a way to make these things smaller..."
In fact, Suzuki made no attempt to downsize its latest GSXR750—rather, the
goal was simply to pare weight and update suspension performance. Chassis
geometry on the '94 remains unchanged, as does the basic drivetrain.
Internally, the new-last-year, liquid-cooled, 749cc engine retains its basic
dimensions and characteristics, but benefits from lighter connecting rods,
magnesium (instead of aluminum) valve and ignition covers and aluminum (instead
of steel) coolant pipes.
Several transmission gears have been lightened via additional machining
and/or hole-drilling. The clutch rack-and-pinion assembly also lost weight, and
transmission shafts are now hollow rather than solid. While they were at it,
Suzuki engineers added an extra dog to second and sixth gears for surer
engagement in what was already the slickest gearbox in the business.
Reading down the list of detail changes, it's apparent that those 19 pounds
didn't come off easily; most of the differences can be measured in grams, not in
ounces or pounds.
While the '94's frame might look identical, it's not. Additional bracing and
thicker aluminum in some areas allowed the use of thinner aluminum in others;
certain sections of frame rail only enclosed on three sides have now been
"boxed" on the fourth. Most obviously, a new bracket on each side of the bike
bolts the cylinder head firmly to the underside of the main frame rails.
Overall, Suzuki says the frame is lighter, but just as strong.
The all-new, heavily braced swingarm is not any lighter than the GP-wannabe,
banana-shaped arm on last year's bike, but it is, according to Suzuki, 5 percent
more rigid. It also looks better, and the fact that it's joined to the frame
with a 25mm pivot shaft (versus 20mm last year) is a definite flex-reducing
move. Chain adjusters are now of sliding-block design.
Controlling that swingarm is a fully adjustable damper similar to last year's, but with a 6-percent stiffer spring and 30 percent more damping in
both compression and rebound modes. That additional stiffness was necessary,
Suzuki says, to deal with the increased grip provided by the bigger rear tire; '94 GSXR750s now come fitted with de rigueur 180/55 Dunlop
skins. And don't forget about the new rear wheel; 650 grams (about a
pound-and-a-half) was shaved via a hub redesign.
Up front, more weight was lost by reducing triple-clamp and outer fork tube
diameter by 1mm. Fork sliders, though, have been bumped from 41 to 43mm in
diameter. Suzuki says fork springs are 3 percent tauter this year, while damping
has been increased by 30 percent—but only in rebound mode. The front wheel lost
450 grams. Brakes now consist of Tokico six-piston calipers squeezing lighter,
drilled rotors. Last year's steering damper gives way to the lighter, under-head
damper used on the GSXR1100.
The single biggest chunk of weight-loss came out of the headlight assembly.
Where last year's bike used two round headlights stuck behind a substantial
chunk of glass, the new light uses a more efficient reflector, and the outer
lens—the one flush with the fairing—is now the only lens. With the lighter
light, Suzuki was able to dump the heavy brace that used to support it in favor
of a single bracket, which mounts the instruments, headlight and the sliding end
of the steering damper. The final bit of weight reduction worth mentioning is
the substitution of an 8 amphour battery for the previously used 10 amphour
unit. Make sure and let us know how well that works on cold mornings in
Michigan.
It occurred to us, on our way out to sample the new GSXR in its intended
venue, that it won't be an act of Congress that makes bikes like this obsolete:
rack-like ergonomics will eventually do the trick. Limber riders of less than
about 5-foot-8 are able to wedge their legs and bodies into the cramped cockpit
without too much problem, but taller riders continue to curse what the bike's high footpegs do to their legs. Ridden alongside the '93 bike on
the freeway, the '94-spec GSXR is a bit less comfortable due to its relatively
stiffer suspension. At least its engine runs smoothly, which takes a bit of the
bite out of the bike's painful ergonomic layout.
Ahhh...curves at last. With the '93 and '94 bikes' legs dialed to
from-the-factory settings, it was finally time to see what Suzuki's chassis
engineers had accomplished during the off season. We headed first to one of our
favorite testing roads, one littered with smooth and tight first- and
second-gear corners. Squeeze the '93 bike's brakes charging into one of those
corners and you get excellent deceleration, stopping power that's better than 90
percent of the sportbike population. The only downside is a lever that grows a
bit mushy after eight or 10 banzai stops.
Then hop on the new bike, blitz yourself up to speed, squeeze the lever and
WAAAHAA! You learn quickly to clamp your thighs to the tank and the sockets
around your eyeballs. The new bike stops hard, its stiffer fork helping
to keep its chin up while doing so. Fade wasn't a problem with the older bike's brakes, but the pads in the new
six-pot Tokico calipers are even better, sporting ceramic heat insulation on
their backs that prevents heat transfer to the brake fluid. The excellent bite
and feel at the lever doesn't change no matter how many times you rail up and
down the mountain.
Despite identical rake and trail numbers, the new bike flicks into turns more
crisply than the old one, a trait due to several factors: 1) increased fork
damping, which eliminates the old bike's tendency to bob slightly during
hard-core turn-ins or severe braking maneuvers; 2) 19 fewer pounds to heave,
several of which were removed from directly above the front tire; 3) thicker,
less flexy fork tubes; and 4) the new front tire, Dunlop's brand-new
Kevlar-belted D204 Sportmax II radial, original equipment on the '94 bike's
front and rear wheels. While the sporting proclivities of Dunlop's GP-compound
Sportmax radials (which were mounted to our testbike at its Willow Springs
introduction) are well-known at the track, the new Kevlar 204 tire might be even
better for quick-flick street riding.
Meanwhile, there's not much to separate the new and old bikes' motors. GSXRs
are not famous for midrange grunt, and reasonable drive requires that the tach
needle remain above at least the 7000-rpm point. Real acceleration begins at
around nine grand, and accessing it on tight roads requires thought and liberal
doses of gearbox use. Pulling from the middle of the powerband, the new bike
feels a bit stronger; chalk that up to weight reduction. Last year's bike ran
11.20 seconds at 121.3 mph in the quarter; the '94's best was 11.16 seconds at
124.05 mph, a bit quicker. And though the new bike ran just 153 mph on top (two
mph slower than the '93 bike), it was three mph quicker in terms of roll-on
acceleration in both fifth and sixth gears.
In creating a GSXR to contend with Yamaha's new YZF and Kawasaki's ZX-7,
Suzuki had to pretty much abandon one of the nicer traits of the '93 machine, at
least on the street. Though the '93 bike unraveled a bit on the racetrack and at
racetrack speeds, it was quite adept at smoothing nasty public roads thanks to
its semi-plush suspension.
The new GSXR, however, offers a decidedly tauter on-road ride. Bumps,
potholes, pavement cracks and other asphalt imperfections are fed more directly
to the chassis, which passes them on posthaste to the rider. This added tautness
makes it somewhat difficult to believe that the fork uses springs that are just
3 percent stiffer than before. Despite this, what feels harsh at low speeds
feels less so as velocity increases, and at about the point where the older bike
begins to lose a bit of its composure, the '94 is just limbering up.
The new bike's redone rear suspension is definitely firmer—though less
jarring than the fork—and does a good job of keeping the rear Dunlop planted
while maintaining a good, level chassis attitude driving out of bumpy corners.
For street riding, the new GSXR becomes a sharper, quicker, lighter tool, but a
considerably less plush one.
What Suzuki sought in retooling the GSXR's suspension is best revealed in its
choice of venue for the new bike's press introduction—Willow Springs Raceway.
Suspension differences between '93 and '94 on that track— where average speed
for a stock 750 hovers around 100 mph—were noticeable, especially through turns
eight and nine, which are decidedly on the high side of 100 mph.
There, the old bike's softer suspension—so compliant and competent on public
asphalt—tended to wallow slightly, giving the rider a bit less feedback and
removing a degree or two of confidence. The new bike, despite its tauter ride,
rails through these faster corners with more composure and crispness.
Early on at Willow, we found the factory settings to be less than ideal, with
a front-high, rear-low chassis imbalance that kept riders from getting the most
out of the bike. To combat this, we fed a bit more preload and rebound damping to the rear shock. We then
firmed up rebound and reduced compression up front. Finally, we dropped the
front end by raising the fork tubes in the triple trees by 10mm. These changes
got rid of the chassis imbalance, quickened steering a bit, and did a far better
job of controlling the bike's wheels at speed.
Tossing the new bike into 90-mph turn two, the slight bob and weave of the
'93 bike was gone. Railing through 130-mph turn eight, the slight wallow of the
old bike had vanished. Its right footpeg and exhaust canister are just beginning
to kiss tarmac as traction runs out. At no point does the new bike feel unstable
or wobbly as it carries on the GSXR tradition of quick, precise and nimble
steering. Suzuki's latest GSXR is now as firmly planted at racetrack speeds as
anything in the class, and despite the fact that the bike offers a harsher
on-road ride, the benefits for those concerned solely with extreme performance
will be happy. The rest may not even notice.
Willow's layout, in conjunction with the GSXR's superior snicky-snick gearbox, makes keeping the tach above nine
grand a snap. Up there it's easy to fall in love with the GSXR; its engine is
one of the all-time smoothies as it pulls to just past an indicated 12,000 rpm
before fading. The new front brake is even more impressive on the track, pulling
the bike down from 130-plus mph powerfully, quickly and controllably.
As hard-core streetbikes go, GSXRs have always been tough to fault. With this
new bike, the faults are even fewer. The ride certainly is firmer and the
cockpit is merciless, but nobody we know of buys a GSXR for comfort. They buy
'em for major-league backroad ability and pit-lane style, and on those counts
the bike is an unqualified success. If you're looking for a more all-around 750,
see the VFR750F test in this issue.
All in all, the race-replica 750-class race is just too close to call this
year. Picking a winner will have to wait until we get a chance to gather all the
contestants at once. Somebody has to do it. We're willing to make that
sacrifice.
The 1994 GSXR750 will be a serious contender. That's a certainty.
Source Motorcyclist 1994
1986 vs 1994 GSX-R 750
Slide it up against our 1994 model and the original GSXR750 looks long, tall
and lumpy. But sliding it onto the scales manifests an enduring appeal
unsurpassed by any 750cc sporting four before or since. Complete with 5.5
gallons of fuel in its oddly shaped tank and 5.3 quarts of 10W40 in its revolutionary air- and oil-cooled engine, Suzuki's
1986 GSXR750 weighed only 464 pounds. Light? How did Suzuki ever do such a thing? It wasn't easy. With a prime directive of undercutting
the curb weight of the average 750 sportbike by 20 percent, Suzuki engineers
settled on a compact, in-line four (more latitude for engine placement than a
V), filling over-square cylinders through four valves each. Liquid-cooling was
out; too heavy. So, the GSXR's engine design team dreamed up an elegantly simple
alternative: use oil to cool as well as to lubricate power-producing parts.
Since cooler parts can be built lighter, the 100-horsepower package was 29
pounds lighter and more compact than its predecessors.
Turning to the chassis, the GSXR's artful aluminum frame weighed in at a
scant 17.7 pounds. Compare that with the 68.5-pound skeleton of its most
immediate ancestor and the fact that it cost roughly 2.5 times more to build than those old steel bones
becomes instantly irrelevant.
The whole package rolled on 18-inch wheels fitted with Bridgestone radials,
with 56.5 inches between the axles, a relatively stubby wheelbase for a 750
sportbike in '86. By fitting the bike with 26 degrees of rake and making it
lighter than anything in its class, engineers expected to establish a new
benchmark for twisty-road handling manners.
When the GSXR hit U.S. pavement in 1986, that's exactly what happened. Light
weight, neutral steering and unflappable stability proved an all-but-invincible
combination. The bike wasn't fault-free, however. It was a bit tall, its
ergonomics were hopelessly cruel and the 31 mm CV carburetors fitted to
U.S.-spec machines left a gaping hole in the middle of the powerband. The faults
were enough to allow Yamaha's 525-pound FZ750 to win our May 1986 "750 Showdown"
by the most marginal of margins.
But even today, beg, borrow or steal a ride on a strong-running example and
you'll see just how effective Suzuki's light-makes-right credo remains.
Effective enough that we can only pray the latest GSXR's 1994 diet program is a sign of
things to come. Because if Hamamatsu could somehow find a way to trim their
latest package down to that 464-pound fighting weight, the rest of the world
would be playing catch-up all over again.
Source Motorcyclist 1994
Any corrections or more information on these motorcycles will be kindly appreciated.