Suzuki GT550: history, specs, pictures

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Suzuki GT550
Also called Indy, GT 550, GT550J, GT 550 J
Production 1972 - 1977
Class Standard
in-line three, two-stroke
Bore / Stroke 61.0mm x 62.0mm
Compression ratio 6.8:1
Top Speed 111 mph (178 km/h)
Horsepower 46.94 HP (35.0 KW) @ 7500RPM
Torque 39.09 ft/lbs (53.0 Nm) @ 6000RPM
Fuel System 3 x 28mm Mikuni carburetors
Spark Plug NGK B8ES '75-77
NGK B7ES '72-74
Battery YUASA 12N11-3A-1 '72-77
Transmission Gear box: 5-speed

Final Drive: chain

Clutch: Wet multi-plate
Final Drive Chain: 530x108
Front Sprocket 16T
Rear Sprocket 40T
Frame Welded mild steel tubing
Suspension Front: Telehydraulic Fork
Rear: Dual Shocks Swinging Fork
Brakes Front: single disc
Rear: expanding brake
Front Tire 3.25-19
Rear Tire 4.00-18
Wheelbase 57.72 inches (1466 mm)
Length 86.42 inches (2195 mm)
Width 32.09 inches (815 mm)
Weight 190.0 kg (wet)
Recommended Oil Suzuki ECSTAR 10w40
Fuel Capacity 3.96 Gallon (15.00 Liters)
Related Suzuki GT380
Suzuki GT550
Suzuki GT750
Competition Yamaha RD350
Kawasaki S2
Manuals Service Manual

Brochures ·

The Suzuki GT550 was a in-line three, two-stroke Standard motorcycle produced by Suzuki between 1972 and 1977. It could reach a top speed of 111 mph (178 km/h). Claimed horsepower was 46.94 HP (35.0 KW) @ 7500 RPM. It was also known as the Indy.

The 1972 Suzuki GT 550 was the big version of Suzuki’s GT range of touring and commuting two-stroke triples. Unlikely to get you in trouble and most certain to get you home, Suzuki’s GT were the thinking person’s two strokes. Bore and stroke were an almost square 61mm x 62mm, giving a capacity of 544 cc. Compression ratio was 6.8:1 and claimed hp was 50 at 6,500 rpm. The five-speed transmission was operated via a multi-disc six-spring clutch.


The engine was a air cooled in-line three, two-stroke. A 61.0mm bore x 62.0mm stroke result in a displacement of just 543.0 cubic centimeters. Fuel was supplied via a port control.


The bike has a 5-speed transmission. Power was moderated via the Wet multi-plate.


It came with a 3.25-19 front tire and a 4.00-18 rear tire. Stopping was achieved via single disc in the front and a expanding brake in the rear. The front suspension was a Telehydraulic Fork while the rear was equipped with a Dual Shocks Swinging Fork. The GT550 was fitted with a 3.96 Gallon (15.00 Liters) fuel tank. The wheelbase was 57.72 inches (1466 mm) long.

1972 GT550J[edit]

  • FRAME #: GT550-10001
  • ENGINE #: GT550-10001
  • ENGINE TYPE: 543cc Two-stroke Triple
  • MODEL CODE: 340
  • COLOR: Redondo Blue, Aztec Gold
  • Front drum brake
  • Headlight mounts and housing primary color

1973 GT550K[edit]

1973 Suzuki GT550K

  • FRAME #: GT550-21780
  • ENGINE #: GT550-23036
  • ENGINE TYPE: 543cc Two-stroke Triple
  • MODEL CODE: 340
  • COLOR: Lime Green, Hermosa Blue
  • Front disc brake
  • Headlight mounts and housing primary color

1974 GT550L[edit]

1974 Suzuki GT550L
1974 Suzuki GT550 in Green
1974 Suzuki GT550 in Green
1974 Suzuki GT550 in Green

  • FRAME #: GT550-36266
  • ENGINE #: GT550-37851
  • ENGINE TYPE: 543cc Two-stroke Triple
  • MODEL CODE: 341
  • COLOR: Hawaii Green, Laredo Red
  • Digital gear indicator
  • Chrome air cleaner covers
  • Chrome rear grab rail

1975 GT550M[edit]

  • FRAME #: GT550-47119
  • ENGINE #: GT550-49302
  • ENGINE TYPE: . . . 543cc Two-stroke Triple
  • MODEL CODE: . . . 341
  • COLOR: Jet Black, Candy Orange
  • Digital gear indicator
  • Chrome air cleaner covers
  • Chrome headlight mounts and housing

1976 GT550A[edit]

  • FRAME #• GT550-61315
  • ENGINE #: GT550-64464
  • ENGINE TYPE: . . . 543cc Two-stroke Triple
  • MODEL CODE: . . . 341
  • COLOR • Forest Green, Targa Red
  • Chrome chain guard
  • Front fender has lower support only
  • Digital gear indicator

1977 GT550B[edit]

1977 Suzuki GT550B

  • FRAME #: GT550-70364
  • ENGINE #: GT550-73451
  • ENGINE TYPE: . . . 543cc Two-stroke Triple
  • MODEL CODE: . . . 341
  • COLOR: Blue, Silver
  • Black headlight mounts and housing
  • Taillight flat on top
  • Digital gear indicator

1972 - 1977 Suzuki GT 550[edit]


IT WAS Colin Curwood freelance photographer of this parish  who really reminded me of the problem. Giving us some Long Distance Information on his 32.000 miles-plus GT550 Suzuki in June he observed that hurling such a machine round Silverstone and then bitching about the handling (as Bike did. many moons ago) is a pretty pointless exercise. Stick your neck, nose, elbows, bum and boots out on the street if that's where the bike belongs. I agreed; I still do. So what was I doing on a 550 in the Isle Of Man ferchrissake? It just didn't seem right, somehow. Race week in the Island without a bike may be strawberries without cream, Coburn without Hughes, but I didn't really fancy my chances of beating Mike Hailwood's angle of lean round the course on a Suzuki triple. Or rather I did, but only after visiting every Bike pub between Ramsay and Peel. Anyway, my route home across the mainland is specifically designed to test any street bike to the outer limits, so I settled for using the 550 as transport, pure 'n' simple.

Until these two maniacs hustled by me one evening, going round the course. The leader was on a Trident, giving his mate on the 750 Honda behind some work to do just keeping the horizon the right way up. I'm well aware that you'd have resisted this vulgar challenge to ego and riding skill and just continued plodding on towards the Chinese meal I was headed for, but I was due on the midnight boat and it was a nice evening and I hadn't really had a good blast all week and ... I tucked in behind the Honda and soon we were cruising in the high eighties, playing tag in and out of cars, combos, tractors and packs of bikes. The 550 was keeping up on the good surface, slipstreaming the four along the straights and nudging him through the bends on braking. Then the road deteriorated with that sort of sudden unexpected brain-loosening lurch you get crossing county boundaries. Using all the 550's amazing mid-range whizz to haul down the straight from one turn to another, I felt my internal organs cannoning off each other like the BBC had decided to hold the final of Pot Black in my visceral region. Liver off kidney down the centre pocket: that sort of thing. I gave in finally cowardice is one of my more attractive attributes and let the throttle slip forward beneath a limp and unresisting wrist. Try it yourself if you don't believe me, but don't eat first, okay?

Lack of rear suspension compliance must be one of the Suzuki's worst points, along with a poor riding position and inadequate fuel capacity. We've said it before about Suzuki's and it still applies. Stiffer springs do not a better handling motorcycle make. We've also moaned about footpegs mounted so far forward that you find yourself hanging your heels on the passenger's rests for some relief on motorway drags. I've seen so many other riders at the same game to know that I'm not alone, but W. Haylock of this address informs me that the new GS750 Suzuki is built to accept normal human beings in reasonable comfort. Perhaps before long Japanese manufacturers will all be building bikes with old-style European riding positions, but until then ...

The GT550's thirst remains a problem in a country where — since the great gas crisis of '73 garages shut up shop earlier and earlier and keep the shutters up on Sundays. Multiply 3.3 gallons by 31 and you get 102.3 miles, which is the sort of distance you can easily cover in a Sunday evening without ever sighting an open petrol station. On three occasions I stretched the 550's limited reserves of fuel and my own patience to the limit, droning along in fifth gear with a handful of revs on the dial. Twice I was overtaken by mopeds in my prayerful search for hydrocarbon distillate. Oh, the humiliation.

But I haven't mentioned the engine at all. Well, there's precious little to say. Mods have been so minor that it almost takes a storeman to spot them. Early electric starter motor clutches gave trouble and that's about it, because we know enough folk with high mileage examples to be sure that you'd have to be rather unlucky to cop an unreliable big triple. Most stunning internal mod on the latest A model is bores machined straight into the cylinder casting sans liners, but coated with Suzuki Composite Electro-Chemical Material (SCEM) or hard chrome time and thee. The GT250 is similarly constructed and benefits are claimed to be better heat dissipation, more constant piston tolerances and, therefore, more consistent power output. SCEM is further claimed to be ultra hard wearing and to present no problems for reboring.

Since its introduction in 1972, the GT550 has changed very little. The front drum finally faded away completely in '73 to be replaced by a single disc. Along with improved ground clearance a year later, this was the most significant performance improvement, and the less said about the original front brake the better. I've yet to encounter an owner who hasn't tried to uprate it in some way. And while we still find it far too easy to knock chunks off the road with the GT380's centre stand, I never succeeded in making its bigger — and much smarter brother kiss the deck. Instrumentation was 'improved' for '75's M model with larger idiot lights under smoked acrylic sheet and a digital gear indicator. I found great reassurance in looking at this instrument and always discovering that the figure displayed was still the right way up: a worthwhile addition for those of a nervous disposition.

Best thing about the rubber-mounted motor is its vast acreage of usable power, spread from anything over three grand right up to the 8,000 rpm redline. Maximum torque a hefty 38.7 lb-fts is developed 2.000 rpm below that figure and it shows in magnificent mid-range pzazz. Even five gears the GT 750's — seem one too many on occasion, so smooth is the urgent surge of three cylinders. But you have to take the rough with the smooth. The Suzuki three may be way silkier than Honda's four most of the time, but just as you're about to sail smoothly over the legal limit at 5,000 rpm in top, an ugly patch of vibration shows up. It lasts from just below 70 mph to just over 80 and hammers through to your feet. There's no alternative to choosing either a 65 or 85 mph cruising speed. No prizes for guessing my choice.

Suzuki's greatest achievement in producing the 550 was to succeed in complete understatement. Inevitably it was compared with the early Kawasaki 500 triples, whose bowel-loosening performance left a legend which has tended to rub off on all air-cooled strokcr threes. Instead the 550 looks staid, almost portly, but. nonetheless, attractive. Its frame may look just like a collection of tubes holding two wheels apart, tacked together with aesthetically repulsive gussetting, but it handles despite the rear springs' attempts to prevent it holding a line. It may not wheelie its way into your affections, but a standing quarter time in the 13 second bracket from 543 cc ain't to be sniffed at.

As I looped across England, the bike really began to grow in my estimation. A quick warm-up down the M6 to Knutsford had us threading in and out of the deadly day tripper traffic I hoped would be well clear of the Peak district by the time I got into the Macclesfield - Buxton - Matlock groove. It's a route well worth exploring if you want to learn something about your riding and the bike you do it on. Combined with stretches of both M6 and Ml and a final mad dash across Leicestershire and Rutland on the A606, it features everything from a series of devastating uphill and down dale hairpins, steep valley descents and climbs and finally a wide, lolloping stretch of blacktop curling over the rolling English countryside. Now that the M62 has drained it of heavy truckers, all you have to contend with are other loons who think it's a great way to go home.

At first I was baulked all the way into Macclesfield by coaches and caravans, until things thinned out on the twisting climb up to the brief plateau before Buxton. Arms splayed round a bulging tank bag, I began to feel speed fever taking over easing the Suzuki into tight uphill curves, picking it up and squirting the power on simultaneously. No wriggles or twitches, just power and plenty of it whenever it was required. So far I'd failed to miss a cog in the positive, if slightly clunky, box and the brakes were holding up under a fair amount of punishment. Even my hind quarters weren't protesting: this is a road which demands total concentration or it's splat into some picturesque stone wall or a long echoing scream down into a charming roadside chasm. Heading down into hairpin after hairpin with precious little engine braking had me grasping the brake lever yet more fervently as I gave in to the tempo of a ride that was rapidly getting out of hand. Under the hypnotic effects of swinging rhythmically through bend after bend I kept on wanting to do it faster and faster and faster still. The brake pedal sagged lower and lower and the disc seemed to require more and more pressure. I'd have given all the digital gear indicators in Hammamatsu for another.

Source Bike Magazine 1974


Make Model Suzuki GT550K
Year 1974 - 75
Engine Type Two stroke, transverse three cylinder
Displacement 543 cc / 33.1 cu in
Bore X Stroke 61 x 62 mm
Compression 6.8:1
Induction 3 x 28mm Mikuni carburetors
Ignition Battery/coil with contact breakers
Ibattery 12V, 11Ah
Starting Electric and kick
Max Power 40 kW / 53 hp @ 7500 rpm
Max Torque 53 Nm / 5.4 kgf-m / 38.8 ft-lb @ 6000 rpm
Frame Welded mild steel tubing
Transmission 5 Speed, constant mesh
Final Drive Chain, endless 530
Front Suspension Telehydraulic fork
Rear Suspension Dual shocks swinging fork preload adjustable
Front Brakes Drum
Rear Brakes Drum
Front Tire 3.25-19
Rear Tire 4.00-18
Dimensions Length: 2195 mm / 86.4 in Width: 815 mm / 32.1 in Height: 1160 mm / 45.7 in
Wheelbase 1465 mm / 57.7 in
Ground Clearance 145 mm / 5.7 in
Dry Weight 200 kg / 441 lbs
Fuel Capacity 12.5 Liters / 3.3 US gal / 2.7 Imp gal

In Media[edit]