Four stroke, transverse four cylinder.
DOHC, 2 valves per cylinder.
Capacity
598 cc / 36.4 cu-in
Bore x Stroke
58.5 x 55.7 mm
Cooling System
Air cooled
Compression Ratio
10.0:1
Lubrication
Wet sump
Induction
4x Mikuni BS32 carburetors
Ignition
Hitachi TID 14-31, Transistor TCI
Starting
Electric
Max Power
72 hp / 52.5 kW @ 10000 rpm
Max Torque
53.9 Nm / 39.8 lb-ft @ 8000 rpm
Transmission
6 Speed
Final Drive
Chain
Front Suspension
Telescopic forks
Front Wheel Travel
99 mm / 3.9 in
Rear Suspension
Monocross rising rate with 5-way preload
Rear Wheel Travel
142 mm / 5.6 in
Front Brakes
2x 267mm discs 2 piston calipers
Rear Brakes
Single 267mm disc 1 piston caliper
Front Tyre
90/90 V18
Rear Tyre
110/90 V18
Rake
64.0°
Trail
106 mm / 4.2 in
Dimensions
Length 2118 mm / 83.4 in
Width 734 mm / 28.9 in
Height 1224 mm / 48.2 in
Wheelbase
1424 mm / 56.1 in
Seat Height
790 mm / 31.1 in
Ground Clearance
150 mm / 5.9 in
Dry Weight
188 kg / 414.4 lbs
Wet Weight
208 kg / 458.6 lbs
Fuel Capacity
21.5 Litres / 5.6 US gal
Consumption Average
56 mpg
Braking 60 - 0 / 100 - 0
- / 36.5m
Standing
¼ Mile
12.4 sec / 107.5 mph
Top Speed
129 mph
.
As a look-alike little brother to the FJ1100, the FJ600
promises true sporting performance. Though a few engine parts were borrowed
from previous machines, the FJ600 is essentially all new and aimed squarely
at sports riders. The 16-valve engine features valve sizes normally reserved
for 750s: 31.5mm intake, 27mm exhaust and the four carbs boast large 32mm
Venturis. Power is transmitted to the chain-driven rear wheel through a
six-speed gear box. A frame-mounted fairing, triple discs, DeCarbon-type
single-shock rear suspension system and long-travel front suspension with
integrated fork brace adorn the short (56.1-inch wheelbase), low-slung
chassis.
1984 Review
Yamaha's middleweight will get its sport
reputation the hard way— by earning it.
With all of the attention that's going to be paid to Yamaha's other new
sport-bikes, the FJ600 just might get pushed out of the limelight. After all,
this straightforward transverse-four middleweight isn't, as is the RZ350, the
triumphant return of two-strokes to U.S. streets; nor is it, as Yamaha proclaims
of its new FJ1100, destined to be 1984's fastest production bike.
And perhaps, in specification, the 600 is unspectacular by 1984 standards. Its
all-new chassis includes Monoshock rear suspension (with preload set via a
remote adjuster), but neither the deCarbon shock nor the air-assist fork allows
damping adjustment. On top of that, the 600 makes its sporting debut bereft of
either a 16-inch front wheel or a square-section tube frame.
For those who adhere to sport chic, that makes
the 600, despite its FJllOO-inspired bodywork, nearly naked at the cotillion.
Discounting the 600 as a sportbike lacking the requisite racy filigree not only
misses the point, though, it dismisses what might well be the best middleweight
sporter for 1984. What's important with the 600 is what's in the package, not
what's missing; and what's in the 600 is sound, established engineering.
The engine is based on the eight-valve Seca 550
powerplant, and is extremely compact. And, more was done to the original 528cc
motor than the bore-and-stroke that brought its displacement up to 598cc. In
revamping the 550's engine Yamaha engineers altered combustion-chamber shape,
valve sizes, cam profiles and timing, carburetor size and airbox capacity, all
to achieve one specific goal: performance. Even fuel mileage took a back seat to
engine performance: YICS, Yamaha's mileage-boosting interconnected inlet
plumbing, was" dropped when it was found the engine pulled stronger—although at
a somewhat higher fuel-consumption rate—without it.
And the resulting powerplant does pull. Below 7000 rpm the engine offers good
power for a middleweight streetbike; nothing is lacking.
Above that engine speed, though, the 600 is all
sport-bike, and easily revs to its 10,500-rpm redline in five of its six gears.
And in sixth, the prototype FJ600 we rode managed almost 10,000 rpm—and an
indicated 125 mph—down Willow's back straight.
Just as important as engine performance is handling, and in that area the 600
gives away very little. At a claimed 415 pounds, the FJ600 is among the lightest
of the sport middleweights, and its lack of excess poundage pays off in every
corner.
And the 600's relatively quick steering geometry
(26 degree Steering Head Angle, 4.17 inches of trail), lets you flick the bike
through those corners without muscling it—and without turning it twitchy at
speed. Hauling down from speed is equally predictable, thanks to the 600's
excellent triple-slotted-disc brake setup; the only flaw we found in the 600's
braking was a tendency toward nosedive in full-on stopping. Overall, from ride
quality to Ground Clearance to ergonomic layout, the 600 displays impressive
performance credentials, either for closed circuits or the open road.
So, even though the FJ600 might be starting 1984 a little out of the spotlight,
we're betting it won't end the year that way.