Four stroke, transverse four cylinders, DOHC, 2 valves per
cylinder.
Capacity
673 cc / 41 cu in
Bore x Stroke
62 x 55.8 mm
Compression Ratio
9.4:1
Cooling
System
Air cooled
Induction
4 x 32 mm Mikuni carburetors
Ignition
Transistorized
Starting
Electric
Max Power
53.2 kW / 73 hp @ 9400 rpm
Max Torque
57 Nm / 5.8 kgf-m / 42 lb-ft @ 8000 rpm
Transmission
5 Speed
Final
Drive
Chain
Front Suspension
35mm Kayaba fork
Front Wheel Travel
150 mm / 5.9 in
Rear Suspension
Dual Kayaba shocks adjustable spring
preload
Rear Wheel Travel
100 mm / 3.9 in
Front Brakes
2 x 275mm discs, 1 piston calipers
Rear Brakes
Single 275mm disc, 1 piston caliper
Front Tyre
3.25 H19
Rear Tyre
3.75H 18
Dry-weight
217 kg / 478 lbs
Fuel Capacity
16 Litres / 4.2 US gal / 3.5 Imp mpg
Consumption Average
5.4 L/100 km / 18.5 km/l / 43.6 US mpg / 52 Imp
mpg
Standing
¼ Mile
12.7 sec / 165 km/h / 102.7 mph
Top Speed
201 km/h / 125 mph
.
Specialization is a fine thing for the motorcyclist who wants a touring bike
or a commuter bike or a sport bike. And it's become essential for the off-road
competition. Still, there's a need for a motorcycle that's big enough for two-up
touring, small enough for easy handling, powerful enough to be fun and
economical enough for commuting. To fill that need, all the Japanese motorcycle
companies make 650 Fours, all of which are fast and smooth, reliable and
comfortable. Somehow the 650cc class has escaped the most extreme designs; there
are no Fours with 16 valves, or 650 V-Twins, no liquid cooling.
Within the class of 650 Fours are four very similar machines, the newest of
which are Suzuki's 650s. Instead of making one model, Suzuki has three; a shaft
drive touring model, a shaft drive with fancy styling and a chain drive standard
model that's about the most all-around motorcycle Suzuki makes. (A model that
hasn't been announced this year is a 650 Katana. It's available in other
countries, which only makes us wonder if Suzuki will yet announce a Katana 650,
possibly with a turbocharger.)
Enough speculation. Suzuki's 650E is here already, having been introduced
last year with the shaft-drive G models. Many parts are shared with the G
models, but the engines and transmissions are not, for the most part, the same.
Because the G models get shaft drive, they get a different transmission. And
that's hooked up to an engine of newer design than the engine on the 650E.
Inside the 650E engine are parts carried over from the GS550. The 55.8mm
stroke is the same and the helical gear primary is the same. To get the 673cc of
displacement, the 650 uses bigger pistons, 62mm across rather than the 56mm
pistons of the 550. Both the E and the G model 650s use the same bore and stroke
and top ends of the engines are identical. Only at the bottom end are they
different, the G model getting plain bearings, the E getting the rollers from
the 550. That difference, of course, means that the G operates with higher oil
pressures and a different oil pump.
The 650 top end, in either version, is a mixture of old-style Suzuki
four-stroke and Suzuki's latest ideas. The 16-valve head with lever-type
followers isn't used on the 650. Like the original Suzuki four-strokes, the 650s
use eight valve heads with bucket and shim followers connecting the double
overhead camshafts to the valves. The shims are on top of the follower buckets,
where they can be changed easily enough, with Suzuki's valve adjustment tool.
Cams don't have to be removed for adjustment on the 650s.
Everybody in Japan is experimenting with intake designs, trying to find new
ways to swirl the mixtures around the combustion chambers for more efficient
combustion. On the larger Suzukis narrow angles between the valves and machined
pockets in the heads provide that swirl. On the 650s, Suzuki offsets the intake
and exhaust valves in the combustion chamber to create the swirl effect.
Aside from the combustion chamber shape, the 650E motor is straightforward
and a good example of contemporary Japanese motorcycle design. There are four
32mm CV Mikuni carbs, the same size as on the GS550, but on the larger engine
they provide better low speed throttle response. The double camshafts are driven
by a roller chain from the center of the crank, a self-adjusting tensioner
maintaining chain tension. Ignition is electronic, with mechanical advance,
mounted on one end of the crankshaft. The alternator is on the other side of the
crank. This is not one of those engines with auxilliary shafts or intermediate
shafts to operate generators or ignition.
Connecting the engine to the drive wheel are a multi-plate wet clutch, five
speed transmission and 530 O-ring chain. Clutch pull is moderate, shifting is
precise and easy and the linkage-connected shift lever has minimal slop. Only
the clutch's reluctance to release interferes with shifting on the 650E.
Particularly when cold, the clutch drags, making shifting hard and neutral
particularly difficult to find. When the bike is warmed up, the problem
disappears and the transmission and clutch are especially pleasant to use.
Five years ago Suzuki introduced the GS750, the first Suzuki four-stroke sold
in this country. It was the fastest and best handling 750 available, a standard
for other big bikes to follow. Since then the GS750 has gotten bigger and faster
and has twice as many valves and noticeably more weight.
What the GS650E has is exactly the same performance that the original GS750
had.
Both the original GS750 tested by Cycle World and this GS650E turned a
12.83 sec. quarter mile. Not just the numbers, but the performance feel of the
machines is the same. Like the original four-stroke Suzuki, the 650 is a smooth
running, easy spinning engine. It has a noticeable power surge over 4000 rpm and
must be spun fast for maximum performance. There is ample low-end performance
for normal use, but at low engine speeds the performance is not the best in
class.
Masking some of the 650's low speed performance are the 32mm Mikuni CV carbs.
The original 750 used slide throttle carbs and Suzuki was one of the last
Japanese companies to switch to vacuum-controlled carburetors. On the 650, as on
other Suzukis, the CV carbs have their own peculiar characteristics. All Suzukis
have fast idle cams that cause the engines to spin at 4000 rpm or more when full
choke is used, and full choke must be used for cold starting. Start the 650 and
it immediately revs to 4000 rpm. In the not-too-distant past, when the choke was
pushed in a touch the engine would die and the procedure of full choke, rev to
4000 rpm, less choke and stall could be repeated several times before leaving
the driveway. It's getting better.
This 650 would still rev too high when cold, but at least the
handlebar-mounted choke lever could be backed off slightly and the machine would
run at 1500 rpm or so. It still didn't run perfectly when cold, but at least it
ran and it wasn't difficult to adapt to when ridden every day. Making it more
difficult to use when cold, the clutch must be pulled in for the starter to
operate, an unnecessary inconvenience and an example of a modern feature that
doesn't make the new bike better than the old.
That similarity to the old GS750 continues over to the handling and overall
size of the machine. The GS650E is 40 lb. lighter than the original GS750,
even-though it has the cast wheels and double front disc brakes that later were
added to the GS750E. And the engine is obviously a Suzuki engine, with chromed
round caps at the end of the double overhead cams. Even the gas tank, a
conservatively styled 3.9 gal. tank, looks much like the tank on the original
GS750. The most notable difference in styling is the tailpiece, which does not
have the original 750's small flare at the back.
In almost every way, this 650 is a better motorcycle than the original 750.
The suspension is similar, in that both are compliant and controlled. But the
650 has air caps on the forks so front end ride height can be changed. And the
damping can be adjusted on the shocks through four settings, ranging from soft
with just enough damping to not-quite-firm with a little more damping. The
adjustments are easy to make by turning the collars at the top of the shocks.
Like most Suzukis, the 650 suspension is as soft as it can be to do the job.
The soft seat accentuates this, but the suspension at both ends is compliant
over small bumps and holes and large ones. With two people on board the
suspension is a little too soft, the back end bottoming on just moderate bumps.
Having a relatively soft suspension doesn't keep the 650 from handling well.
Those who believe a suspension works best when it doesn't work might be offended
by the pitching and compression going on underneath the 650.
Being 40 lb. lighter than the original 750, the 650 is just a little easier
to turn. The handlebars are moderately wide and long, painted black as are many
pieces of the new 650, and they make easy work of fast direction changes on the
650. Like the original Suzuki four-stroke, the 650 is stable and secure in
corners, possessing adequate cornering clearance for any street fun before the
various stands scrape. The folding footpegs do a nice job of informing the rider
that the end is near, Beware. Maybe even repent.
Better yet are the brakes. Suzuki has been doing a superb job in recent
years, making brakes that are powerful and controllable and require just the
right amount of lever effort. The 650E brakes are standard issue Suzuki, meaning
as good as they come. The double front discs -have all the power the tire can
handle and the response to lever pressure is progressive and gentle, so it's
easy to keep the tire from locking. The rear disc is similarly controllable so
it, too, is not prone to locking during hard braking. Stopping distances are
excellent: 27 ft. from 30 mph and 125 ft. from 60 mph.
Comfort has also benefitted from development. When the original GS750 was
being tested, Suzuki began trying different types of foam and shapes of seats.
The first GS750 wasn't perfect, but from that beginning Suzukis have gotten
better and better seats. Now the GS650, like most all other Suzukis, has a
superior seat. It is soft and wide and shaped so one or two people can spend
hours on the bike without pain.
Other comfort-related parts are just as well done. Handlebars aren't quite as
much wheelbarrow-style as those of the earlier Suzukis, due probably to the
shorter wheelbase of the 550-derived machine. The black-painted bars are a
comfortable distance from the seat for normal use. And the angles aren't bad
either. The pegs, again, are in a normal enough position. Despite not having a
rubber-mounted engine or rubber-mounted bars, very little vibration comes
through to the rider. At speeds up to about 65 mph the Suzuki is particularly
smooth, the vibration being well damped by the pegs, seat and rubber under the
gas tank. Above that speed or on deceleration some vibration comes through the
handlebars. In its class the GS650E is one of the smoother machines, because it
never has an annoying vibration period the way some of the other machines do,
even those with rubber-mounted engines.
Some of the Suzuki's above-average comfort is derived from its above-average
size. It is a little larger motorcycle than the Yamaha 650 Maxim or the Honda
CB650. The seat is a little taller and the rider feels as though he's riding a
bigger bike, even though the 470 lb. Suzuki is not noticeably heavier than other
650s.
Most of the changes that have occurred to the 650 since its introduction last
year have been to parts that the rider operates or watches. There's a fuel gauge
now, an accurate gauge, too. The choke control was moved from the steering head
to the left handgrip where it is easier to operate. A new control pod integrates
the signal light switch with the high beam control in a single, easy-to-use
lever on the left handgrip. The 650E does not have self-cancelling turn signals,
though.
The only other changes to the E this year are the air caps on the forks and
the damping adjustments on the shocks, both parts that were used on the 650G
last year.
Despite the E and G models performing remarkably alike, the difference in
parts is noteworthy. Things like fenders and tailpieces and brake reservoirs are
different, even though they do the same job and look so similar. Most of the
differences are in trim. The shaft-drive G uses many chrome parts where the E
uses black painted parts for fork sliders, handlebars, shocks, signal light
housings and mirrors. Wheels are different on the two machines, the G using the
new-style Suzuki cast wheels with tubeless tires, the E using tube-type tires.
Rear tire size is also different, the E using a 3.75H-18 rear tire, while the
shaftdrive bike uses a 17-in. rear tire.
If the combination of parts shuffling has an effect, it is to make the E look
more spartan. Neither model is really striking in appearance, but the G has a
little more brightwork.
If the GS650E has a flaw, it must be styling that is in such good taste that
it might not get noticed. In performance, nothing in its class is better. It is
the fastest 650 tested to date. It has no handling quirks. It's fun to ride on a
variety of roads, yet it lacks visual excitement.
All the motorcycles in this size-category are now good enough that
performance may not be enough. Suzuki has a wide variety of 650s, from the
chopper-styled L to the touring G to the basic E, but the E is the most sporting
of the lot so far. The Katana hasn't been announced. And even if it is, the E
could get lost in the shuffle.
If, however, tasteful good looks and black or dark blue paint jobs appeal to
you, the GS650E could be your dream bike. It exudes a do-it-all competence that
needs no apology. It is a well thought out design that has proven to be
dependable and long lasting. Add to that a size that has proven useful since
Britain last won a battle, and the GS650 in any of its permutations is an
appealing motorcycle
Source Cycle World 1982
Any corrections or more information on these motorcycles will be kindly appreciated.