Suzuki GS400S

Suzuki GS400S
Manufacturer	Suzuki
Also called	GS 400 S
Production	1984 - 86
Class	Standard
Engine	Four stroke, parallel twin cylinder, DOHC, 4 valves per cylinder.
Compression ratio	10.0:1
Ignition	Transistorized
Transmission	6 Speed constant mesh
Suspension	Front: Telescopic, coil spring, oil damped Rear: Dual dampers, coil spring, 5-way adjustable
Brakes	Front: Single disc Rear: Drum
Front Tire	3.00S184PR
Rear Tire	3.50S184PR
Wheelbase	1420mm / 55.9 in
Seat Height	755 mm / 29.7 in
Weight	177 kg / 390 lbs (dry),
Recommended Oil	Suzuki ECSTAR 10w40
Fuel Capacity	16 Liters / 4.8 US gal
Manuals	Service Manual

Engine

The engine featured a 10.0:1 compression ratio.

Chassis

It came with a 3.00S184PR front tire and a 3.50S184PR rear tire. Stopping was achieved via Single disc in the front and a Drum in the rear. The front suspension was a Telescopic, coil spring, oil damped while the rear was equipped with a Dual dampers, coil spring, 5-way adjustable. The GS400S was fitted with a 16 Liters / 4.8 US gal fuel tank. The bike weighed just 177 kg / 390 lbs. The wheelbase was 1420mm / 55.9 in long.

Photos

Overview

Suzuki GS 400S

Build a better motorcycle and the world doesn't necessarily beat a path to your door. For several years now Suzuki has built one of the sweetest small-displacement twins available. The bike continues to impress us in its latest incarnation, the GS400S, as a sound, practical and fun motorcycle, especially for learners, riders of small stature and city dwellers. Suzuki recognized the need to draw more attention to the GS400's merits, and in '84 has tarted it up with flashier gold wheels, new paint and a nose fairing on the CS400S model. The mechanical package remains largely unchanged, but there are a few refinements. Suzuki has left the engine untouched for the '84 model, except to paint it black with matching exhaust pipes, and the DOHC. four-valve twin remains a winner. A gear-driven counterbalance smooths the imbalance of a 100-degree parallel twin to the extent that the GS400 is smoother than most of Suzuki's fours. Carburetion is crisp and the engine pulls well from low revs to redline without any hesitation or flat spots. Power comes on most strongIy above6.000 rpm., but you don't need to row through the gearbox for ordinary street use, nor is it necessary to keep it pinned at red-line for a sporting ride. The exhaust noise seems unexciting, and overwhelmed at low speed by the engine's mechanical noise, but the GS400S is a quiet motorcycle. During our last test of the '82 GS400 we recorded a quarter mile time of 14.16 seconds at 146 km/h (91 mph), which puts the small Suzuki into a sporting realm. But its mild manners und low-speed pulling power also make it well suited to learners and commuters, In additlon, the GS400S returns good fuel economy: 4.4 L/100 km (63 mpg (during our test despite some hard use and break-in mileage). The tank holds 16 L. providing an excellent range of 358 km and the fuel gauge is accurate enough to be useful until reserve is reached. Suzuki has moved the choke from beside the carburetors to its proper place on the handlebar, where it is easily adjustable for cold morning starts. The engine warms up fairly slowly, but can be ridden off under choke.

The clutch drags slightly on cold mornings, and the transmission works better when it's warm too. Shifting action is usually positive and light, but neutral can be occasionally difficult to find. The gearbox would work better if the shift lever weren't so short. Most riders shifted with the top of the foot rather than the toes, and found the effort sometimes painful. You can work around the problem by moving your fool back for each shift. Since sporting motorcycles have made huge strides in recent years, the GS400S seems less impressive than its paint and styling would suggest. But it's still a capable and entertaining bike at low and medium speeds, where steering is precise and effortless. Light weight and a reasonably rigid chassis and firm suspension help, but the GS400S predictably loses its composure at higher speeds where it begins lo wallow and weave. The rear shocks are the most obvious culprit, being noticeably underdamped. but their performance is adequate for a budget mulorcycle. Stability on Ihe highway is fine for a lightweight bike, though it is unavoidably susceptible to crosswinds. Suzuki has upgraded the front suspension this year with air caps on the fork, and the front end works well in absorbing bumps and maintaining both comfort and control. The recommended pressure setting is 50 kPa(7 psi). The factory would have been well advised to have hailed its development of the front end at this point, but unfortunately continued and added Suzuki's much-criticized hydraulic anti-dive on the left fork leg. Extra pressure in the fork is already sufficient to control dive, and the anti-dive has the usual effect of creating a mushy feel at the lever for the front disc. The single disc has enough power to lock the wheel, but only with high effort, and approaching lockup is difficult to sense because of the brake's vague feel. The rear drum, on the other hand, is powerful yet easily controlled. New this year are the gold-anodized rims in the same pallern as Suzuki's bigger sport bikes, but the width of the rims is still very small. The budget-variety Bridgestone 3.00S18 front and 3.50S19 rear tires are skinny and look out of place on an '84 bike. Meatier rubber would be welcome. The GS400 is one of the most comfortable small bikes to ride, with a low, comfortable seat and a semi-sporling relationship belween the pegs and handlebar that make an almost ideal sealing posture. A good owner's manual comes wilh the GS400S and allows an owner to perform most basic maintenance by following the instructions. The oiled-foam air filter is easily reached once the seat is removed. The styling and paint of the GS400S are hard lo fault. The bike is handsome and the quality of finish excellent. Instrumentation is clear, and a digital gear indicator proves useful at times. Our test model had been hastily set up. and the sidestand indicator light and oil light were malfunctioning. but otherwise the Suzuki was problem-free. Source CYCLE CANADA 1985

Make Model	Suzuki GS 400S
Year	1984 - 86
Engine Type	Four stroke, parallel twin cylinder, DOHC, 4 valves per cylinder.
Displacement	399 cc / 24.3 cu in
Bore X Stroke	67 x 56.6 mm
Compression	10.0:1
Lubrication	Wet sump
Induction	MBwni BS34SS
Ignition	Transistorized
Starting	Electric
Max Power	29 kW / 39 hp @ 9500 rpm
Max Torque	31.4 Nm / 3.2 kgf-m / 23.2 lb-ft @ 3000 rpm
Transmission	6 Speed constant mesh
Final Drive	s530 chain
	6-speed. Final Drive: , O-rlng seeW Overall Seat Height: 755 mm (29.7 in.) Wh«elbase 55.9m.)
Front Suspension	Telescopic, coil spring, oil damped
Rear Suspension	Dual dampers, coil spring, 5-way adjustable
Front Brakes	Single disc
Rear Brakes	Drum
Front Tire	3.00S184PR
Rear Tire	3.50S184PR
Dimensions	Length 2105 mm / 82.9 in Width 755 mm / 297 in Height 1160 mm / 45.7 in
Wheelbase	1420mm / 55.9 in
Seat Height	755 mm / 29.7 in
Ground Clearance	145 mm / 5.7 in
Dry Weight	177 kg / 390 lbs
Fuel Capacity	16 Liters / 4.8 US gal