.

Suzuki GS 550M Katana

.  

Make Model

Suzuki GS 550M Katana

Year

1981

Engine

Four stroke, transverse four cylinders, DOHC, 2 valve per cylinder.

Capacity

549 cc / 33.5 cu in
Bore x Stroke 56 x 55.8 mm
Cooling System Air cooled
Compression Ratio 8.6:1
Lubrication Wet sump

Induction

4 x 34mm Mikuni carburetors

Ignition 

Transistorized
Ignition Timing 15º BTDC below 1500 rpm / 40º BTDC above 2350 rpm
Spark Plug B8ES NGK, N60R for real performance
Battery 12V 14Ah
Starting Electric

Max Power

40 kW / 53.7 hp @ 9400 rpm

Max Torque

41 Nm / 4.4 kgf-m / 32lb-ft @ 8200 rpm
Clutch Multiplate, wet

Transmission 

6 Speed 
Final Drive Chain, Daido D.I.D 530 'O' Ring, approx. 100 links
Primary Reduction 1.977:1 (87/44)
Final Reduction 3.400:1 (51/15 - UK) / 3.267:1 (49/15 - US) / 3.333:1 (50/15 - Italy)
Gear Ratio 1st 2.666 / 2nd 1.777 / 3th 1.380 / 4th 1.173 / 5th 1.045 / 5th 0.956:1

Front Suspension

35 mm Air assisted forks, 2-way spring preload adjustable

Front Wheel Travel

145 mm / 5.7 in

Rear Suspension

Dual shocks, adjustable spring preload and rebound damping

Rear Wheel Travel

85 mm / 2.2 in

Front Brakes

2 x 275mm discs, 1 piston calipers

Rear Brakes

Single drum

Front Tyre

3.25-19

Rear Tyre

3.75-18
Dimensions Length 2100 mm / 82.7 in
Width     720 mm / 28.3 in
Wheelbase 1435 mm / 56.5 in
Seat Height 740 mm / 29.1 in
Ground Clearance 160 mm / 6.3 in

Wet Weight

215 kg / 452 lbs

Fuel Capacity 

22 Litres / 5.8 US gal / 4.8 Imp gal
Reserve 4.0 Litres / 1.1 US gal / 0.88 Imp gal

Consumption Average

5.7 L/100 km / 17.4 km/l / 41 US mpg / 49.2 Imp mpg

Top Speed

167 km/h / 104 mph
 

ContentsWhich of the following statements is nearest the truth?
A) Middleweight motorcycles are good value because they offer reasonable power and low weight at a sensible price;
B) middleweight motorcycles are dull as ditchwater because they're so sensible;
C) anything less than the ultimate is well, less; or
D) starting features with a question is cheap-shot journalism.

The right answers are A, C, and particularly D, which is an immutable cosmic principle and the first sentence is only there because I've been sitting here for three days chewing fags and trying to think of some way of opening without making excuses for what is ultimately a very satisfactory Suzuki.

The usual scenario was something like this: I'd pull into a car park and kill the 550 Katana's motor, which'd start ticking and pinging as it cooled down after a thoroughly enjoyable bit of headbanging scratching. Then some Derek would waddle over, cast a highly critical eye over the space invader styling and, in tones laden with remorse for the heartbreak he was certain he was about to cause me, impart the knowledge that the Katana's motor and frame were more or less straight 1977 GS550.

Er, yes that's correct. Oh, I see. He means the Katana's merely a dinosaur masquerading as a creature from outer space and he thinks I've paid more than fifteen hundred quid for a prehistoric relic. Yet another punter bludgeoned into believing that anything which isn't next year's model isn't worth the paper its specifications are printed on. Rubbish. So long as a motorcycle does the business it's immaterial whether the basic structure's five years old or fifty, even if the Japanese have seen to it that motorcycle design is becoming like politics, where a year is a very long time.

But argument is useless under such circumstances; the only thing to do is scoot off using maximum revs, execute a scraping 180º turn at the nearest roundabout and go home to inspect the shards of rolled rubber dangling from the right footrest. In any case, my smirking informant was off the mark.

The well-tried dohc 549cc engine with its almost square bore and stroke is not quite the same mill whose excellently useable characteristics won it many friends when it powered the old GS550. That bike had a set of four 22mm slide carbs but these were dropped in favour of 32mm Mikuni CVs when the Katana was introduced last year. This is the most noticeable change - the CVs have sharpened the 550's throttle response considerably, though any improvement in fuel consumption is probably more than offset by the greater encouragement to spin the motor hard through the gears. Power is said to be up by 2.7bhp to 53.7 at 9,400rpm (9,000rpm on the 550E roadster). Frame changes are minuscule: 0.3º more rake and 1 mm more trail - the Katana's own mother wouldn't have difficulty recognising it.

Suzuki obviously felt that the GS could make the transition to Katana-ised form without major trellis changes or the addition of TSCC, TDCC or other ways of making mixture hop around the pots for added oomph. When the GS was introduced, the aim was to provide middle-of-the road performance for people who felt they could do without the extra power and expense of a 750 but enough attention was paid to handling and braking to make the GS a very competent roadster.

Thus, unlike the two 650cc shaft-driven Suzuki’s whose motors have very different power outputs and characteristics, the two 550s share almost identical motors with a conventional two-valves per cylinder layout and a comparatively mild 8.6:1 compression ratio.

Get yer knee down!Because of all the foregoing, the 550 Katana can't be considered as a member of the 'new generation' of sporting light middleweights like the Kawasaki GPz550 or the all-new Yamaha XZ550 V-twin and Honda's 16-valve CBX550 four. It relies instead on improved looks and handling to help proven motor and frame make up for rather excessive weight. Fortunately, the formula works pretty well and it wasn’t long before the 550 was winkling its way into my affections in the same way as the 650 Katana did last year. The business of making a good first impression was, I’ll admit, helped immeasurably by Heron Suzuki GB Ltd’s move from a dingy base down a mean lane in the armpit of West Croydon to a super-spiff HQ in Crawley, West Sussex.

The 550, like all Suzuki test machines, had been immaculately prepared. The motor felt taut and whipped through its revband emitting a characteristic Suzuki coffee-grinder growl though it felt noticeably down on power compared to the 650. Nevertheless it rolled rapidly up to an indicated ton-ten on the slight downgrade leading away from the motorway junction and cruised easily enough at 8,000rpm and 90mph until the M23 ran out at Hooley. Riding position on the two middlesize Kats is very similar: knees tucked right under the tank cut out thanks to the high-set pegs' close relationship to the rider's dip in the seat; arms stretched out over the humped five gallon (23 Litres , metrication junkies) tank to the wide, flat black bars. The racy crouch leans you on to the wind and goes some way to reducing the tall top heavy feel transmitted from the 31in high seat and 40lb (18kg) of fuel in the full tank, but in spite of the shortish 57.5in (1460mm) wheelbase this is no small bolide in its proportions.

As soon as I hit single-carriageway traffic it became clear that the Suzuki packs its power well into the top end of the rev range. In fact there's bugger all to speak of below four grand and its traffic character is strongly reminiscent of Honda's old 400-4 without, thank goodness, the heavy clutch action.

All the same, I nearly dropped myself in the melangwa a couple of times before I got the message that point-and-squirt tactics required a generous handful of throttle and full use of the three, widely spaced lower ratios. Once the mill was well and truly spinning the short-shift lever would snick lightly back and forth between ratios but in heavy, slow moving traffic it quickly became notchy and sticky, with odd clunks lashing through the transmission as the clutch went home. That was about the sum of bad behaviour from the transmission, however, and the clutch stood up to a much heavier than average pounding at our test track.

The Kat's slow-speed steering is commendably quick considering its generally good straight-line stability at speed but its high centre of gravity tends to make it roll around, though it was nimble enough to maximise use of the extremely positive front discs. Those twin discs at the front with their natty red-painted spiders, rims and callipers are excellent stoppers. They have a nice progression from bonking to a halt at 20mph using just a pair of fingers on the black, dogleg lever to tyre-howling deceleration from full honk. At the rear is that rare bird, a double live piston Japanese calliper working on a 10.75in (275mm) disc, again carrying quantities of stop-faster orange/red paint. Frankly, it's overkill in the stop stakes, especially as the old GS's rear drum was easily sufficient. On the plus side, the foot pedal transmits useful feel on gentle applications but unless you literally tread carefully in emergency stops (when it's damn hard to do so, of course) the back wheel tries to come round and visit the front.

Chase that GPz550...Cresting a rise at Purley straight after collecting the Katana, I was greeted by the sight of wall to wall Strom clouds over London but the absolutely torrential downpour they dumped on me was the only rain which fell during the test. With a curtain of rain teeming down and the streets awash, the brakes and tyres coped well enough in rush hour traffic but I'll have to rely on past experience of Suzuki stoppers to say that they'd probably manage well on the open road.

The next two weeks were unseasonably dry - warm even - and most days the sun shone on the faintly bizarre lines of the Katana.

Apart from the conventional layout of headlamp and instruments on the steering head, the 550 and 650 are muted versions of the two biggest multis. The 550's tank is more squat than the rakishly canted version on the GSX1100S, splaying out to the width of the camboxes and relying on the hump round the locking filler cap and the Suzuki logo slashed down the knee cut outs for Katana effect. The front-flip of the two-tone vinyl seat is much less pronounced than the 1100's and the rearward placing of the rider's portion cuts pillion accommodation to a sparse platform. This rests on an ugly plastic moulding housing the large stoplights and a meagre excuse for a rear mudguard.

The plastic front mudguard is oddly humped in the middle and, being too flimsy to brace the forks and too skimpy to keep much crud off motor or rider, is the least effective part of the design. The black anodised finish on the four into two exhaust system still looked okay on the W-registered test machine though the excellent attention to detail on the rest of the machine was let down by ugly daubs of corrosion-resistant matt black paint round joints on the pipe junctions. Close examination of the black frame paint shows it to be a subtle eggshell finish. The brakes, shock absorber springs and even the HT leads are finished in red and the wheels painted white on the principle that if you can't be wild you can still be whacky.

What has really been improved is that usually neglected section of Jap bikes, the suspension. Ignoring the fashionable trend towards air springing, Suzuki have equipped the Katana with coil spring front forks easily firm enough for its naughty fully-fuelled-up weight of nearly 5001b (227kg). A rubber cap on top of each fork leg conceals an adjuster giving two choices of spring preload setting, while at the rear four damper settings on a click ring atop each shock and five spring preload setting give dial-what-you-like suspension.

It all works. Even the softest front setting is comfortably non-soggy and the rear allowed me to set things up the way 1 wanted and yet tolerated the addition of a passenger without losing so much effectiveness that a change of setting became imperative.

Mid spring preload at the rear and softest damping gave a firm ride but allowed the rear end to undulate for a few yards if set off by a bump; increasing the damping put a stop to that but had the rear tyre leaving the road on really bumpy sections. Fortunately, the only time it could be persuaded to leave the ground in a bend was when I took an off-camber right hander near my home at 80mph instead of the 50mph normally dictated by the far less effective suspension on my own XJ650 Yamaha. The Kat gave one bar-churning wallow and settled down without so much as a wriggle.

Static ground clearance is 6.3in (160mm) and the first thing to touch down on right handers is the footrest, even though it's carried high and well rear set on the bottom tube of the pillion peg's subframe. Trying harder calls for an exaggerated body-off posture to make up for the high weight distribution but at that point the back of the petrol tank and the ski slope on the front of the seat start levering your feet off the footrest. Rest assured, it's possible to drag the undercarriage through bends, though rarely necessary.

Heading for the MIRA test track (near Nuneaton in Warwickshire) up twisting A roads north of Aylesbury, it was clear that this is one Jap multi whose power output is well within the range of its frame and suspension. Holding 80-90mph on the clock uphill, down dale and through the wide bends meant making fullest possible use of the top three gears even though only 500rpm separates each ratio. On the motorway with its different sense of time and distance, 110mph had seemed to come up on the speedo fairly rapidly but now the 550 seemed to struggle to hit the ton before a bend or a dawdling Metro driver necessitated a roll-off.
Low, flat 'bars of Suzuki's GS550 Katana are comfortable and good at high speed...
GS550 Katana Handlebars.

I kept expecting Roland Brown to come steaming past on the Laverda Jota 120 (tested elsewhere this ish) but he seemed to be having difficulty reconciling the beast's attention-drawing noisiness with the state of his licence - not a problem with the heavily silenced Katana; it does make some pretty rabid noises at 10,000rpm but they don't carry very far. The tubeless Bridgestone Mag Mopus tyres behaved impeccably apart from a trace of white-lining. Nothing else seemed capable of throwing it off line so by the time we reached the test track I was mightily impressed apart from a stiff neck after 80 miles craning into the wind.

At MIRA the 550's age made itself felt when it managed only 111.35mph running with the wind and with yours truly doing his Smallest Human Being On A Motorcycle impression to reduce air resistance as much as possible. The two-way average worked out at 108mph, while I must have done a dozen clutch-frying launches off the line before accepting that 13.94 seconds is as fast as a 550M will cover a quarter-mile.

Maybe that's not so bad for a bike giving away a supposed nine bhp and 30-odd pounds weight to the Kawasaki (GPz550). We'd also filled the tank before speed-trapping the Katana and it did find a couple more mph after 35 miles at or near the redline had worked through a gallon of juice. It refused to rev past 9500rpm in top, even with a light tailwind, and only just revved to the redline in fifth when, thanks to the closeness of the two top ratios, it was pulling the same speed. Fact is, the 550's got a weight problem. At 475lb (215kg) with only one gallon of fuel on board it's not surprising it can hardly outrun a 500cc, 364lb (165kg) Guzzi Monza even though the latter only has 48 Italian horses to call on.
...it's a fair stretch over the big petrol tank though.

Judging by the graunching noises down below during the most, er, determined attempts at a sub-14 second standing quarter-mile time, the 10,000rpm redline means what it says but the long suffering mill didn't appear to sustain any damage. Only problem during the test was the Katana's prodigious thirst for oil: two pints disappeared in under 1000 miles but this was a machine with 7000 road test miles on its odometer - probably equivalent to three times that many in the hands of an owner rider.

For the rest, the Katana's an almost-normal, well equipped Japanese motorcycle from its bright 60/55W headlamp to the big stop/tail light. The mirrors give a good view of more than your elbows but flap around on their rubber mountings so much that the anti vibration effect is cancelled out. The 550's pretty smooth anyway, except for a slightly rough patch at 5000rpm.

The latest (tenth?) version of thumb rocker on the combined indicators/dip switch is the easiest to use so far and the choke knob is conveniently placed for operation, if not maintenance, on the headstock. The 550 never failed to start first stab on the button. Unlike most other Jap bikes, there's no pilot light position on the lights on/off switch - at least it prevents owners doing what I once did: riding 20 miles home along the A40 under streetlights one night, not realising I didn't have the headlight on until I did a 60mph right turn into pitch darkness at Tatling End . . .

The seat's of the lift-off variety with room underneath for the usual Oriental spanner set but not much else. The locking mechanism was a vast improvement over the last one I came across (on a GSX400 twin) but it's the shape of the seat rather than its removeability which could make or break the 550 Katana in most rider's eyes.

Riding gently out of consideration for passengers resulted in fuel consumption around the 57mpg (4.96 litre/100km) mark, while normal one-up riding making fairly extensive use of the last few thousand revs would drop the Katana down to 50mpg (5.65 Litres /100km). Full use up to the redline in every gear shoved it down to only 35mpg (8 Litres /100km), though you'd need a lot of wide, empty, fuzz-free road to achieve that.

Given the large capacity fuel tank, this means the Katana will run almost 200 miles before going on to reserve, quite a bit further than the cooking' 550E version. The latter is more of a good all round compromise between two-up comfort on long trips, and adequate performance and handling on solo Sunday afternoon blasts down a favourite section of road. In just about all respects the 550 falls midway between the £1238 GSX400F four (105mph) and the shaft driven 65Occ Katana (120mph). The 400's really a big 'little bike' and there's a significant difference between the effort required to cruise at 9Omph on the 400 and on the 550. The extra poke available from the 650, plus the benefits of maintenance-free shaft drive, may sorely tempt riders to pay up the extra £190 and resign themselves to a slightly higher insurance premium. The 650 handles just as well as its little sister but has a tad more low down grunt for traffic while dishing out enough extra horses to make activities which are simply fun on the 550 more exciting.

Source Bike - June 1982