Suzuki GT380

Suzuki GT380 Road Test

Suzuki GT380First seen in 1971, the Suzuki GT380 showed much promise, on paper at least. If the other Japanese manufacturers had stood still during the 70s then the GT380 would have made perfect sense. As machines from the era go, the GT, or Sebring as it is known in the states, is a delight albeit a tad heavy. The air-cooled triple is not at all slow, but never quite as rapid in a straight fistfight with some of the middleweight twins. Touring, rather than street racing, became the natural category for all of the Suzuki triples as they bristled with mod cons and niceties, making them bulky and overweight. There was much advanced thinking behind the design however, the most useful of all being the gear indicator, introduced in 74, situated right in the middle of the instrument cluster.

Unusually the exhaust system bucked the modern two-stroke thinking of one tuned exhaust per cylinder, the middle pot vented to the outside world by means of split exhaust arrangement that saw the header Bifurcate, or split into two, before exiting out of each side of the machine. This gives the GT range a huge look and adds to the all up weight considerably too, which doesn’t help the meagre 38 horses drag the big machine along any better. The mildly tuned 371cc engine is a complex design too, the lubrication system feeding the bottom and top ends of the power plant individually. A notable feature if the triples is the Ram Air cylinder head, reckoned to aid cooling however this was short lived and was not seen on later Suzuki two strokes despite them being more powerful and supposedly in need of extra cooling assistance.

GT380The GT380 saw some minor improvements every year of its production; this was never enough to bring it to the forefront of the capacity class. high fuel consumption of the design was suddenly an issue, especially during the fuel crisis of the 70s. Suzuki effectively ended the run of its two-stroke models by launching its highly popular GS series. In 1976 the GT380 was considered as an old-fashioned bike from the early 70s while its rivals were not. There was nothing wrong with the bike, the engine was nice and its power band was nearly as wide as the rev range, the clutch was easily controlled and the shifts were quick and precise. The sixth gear was a cruising gear, good for long flat stretches and when the rider needed more power in hands the fifth worked well with not much extra fuel consumption.

The handling was considered excellent within the bike’s limitations. It was stable and steered well. The original suspension didn’t react properly to high speed bumps but in the end this wasn’t what the bike was built for and was far happier cruising along the freeway rather than ripping up the twisties. The problem was that the GT380 looked and performed like a touring machine. Its rivals, like Honda CB400F, Yamaha RD400C and Kawasaki KH400 looked sportier, had cast wheels, were lighter, and were faster too.

The GT380 was discontinued in 1978 although models could still be found in dealers as late as 1980.

Suzuki GT380GT380 for Italy
A marketing anomaly concerned the GT380. The actual engine displacement as introduced in the 1971 was 371cc and stayed this way until the end of production. However, for the Italian market only, the GT380 received a displacement increase to 384cc starting with the 1975 model. This enabled Suzuki to get around an Italian government import ban on bikes less than 380cc and less than 170 kg. Suzuki simply increased the bore of the GT380 to 55 mm, thus making the engine capacity now 384cc. Suzuki also made sure that the data plate riveted to the frame showed a weight of 171 kg.

GT380 Model history

1972 Suzuki year code: J start frame number: GT380-10001

The J model suffered from several anomalies not least the front drum brake that proved to be barely adequate, and was replaced with a disc brake the following year. The fuel tank cap had a lock in it, an unusual feature at the time, as was the rubber lip seals for the spark plugs, keeping moisture from shorting out the system. The cylinders of the GT380 were cast as three separate units and each piston was fitted with a not-removable cast-in iron liner while the cylinder head was cast in one piece. A heavily revised model was released in April 1972.

1973 Suzuki year code: K start frame number: GT380-30919

The GT380K had a 275mm brake disc at the front, mounted on the right side of the wheel with the caliper in front of the fork leg. It was a vast improvement compared to the drum brake, but only if the weather was dry. A warning sticker was attached to the fork leg saying ”Caution, braking performance at beginning of the application may change with wet brake disc”. Some changes were made to the frame and exhaust system to provide more ground clearance and reduce vibration.

1974 Suzuki year code: L start frame number: GT380-43732

The GT380L had different carbs than all the other models. The carburettors were changed to constant velocity type along with a change to the air filter box, which meant that the 380 lost one horsepower. A cooling fan was available as an option for the American market. Final drive sprockets were changed to raise the gearing and a gear indicator was fitted to the instruments. The Ram Air cover has a smoother shape and lost its fins. Headlight brackets and shell were now chromed as was the chain guard and air box. The earlier gunmetal alloy finish of the engine became natural lacquered alloy. The dummy air scoops were removed from the side panels.

1975 Suzuki year code: M start frame number: GT380-65984

The GT380M model saw the carburettors revert back to the previous slide type. Otherwise the model remained virtually unchanged, except for a new color scheme.

1976 Suzuki year code: A start frame number: GT380-86754

No changes were made for the GT380A.

1977 Suzuki year code: B start frame number: GT380-95063

The GT380 was still selling well but the number of units built had dropped to less than 10,000 units a year, compared to the 30,000 units in 1972. Only cosmetic changes were made to the 1977 GT380B. The models between 1975 and 1978 looked similar with just the black side covers making it easy to identify the last model.

1978 Suzuki year code: C start frame number: GT380-105000

Suzuki GT380 Specifications

  • Engine -Air-cooled piston-port triple
  • Capacity – 371cc
  • Bore/stroke – 54 x 54mm
  • Power – 38bhp @ 7500rpm
  • Torque – 28ft-lb @ 6500rpm
  • Carburation – 24mm Mikuni
  • Transmission – 6-Speed wet clutch chain final drive
  • Frame – steel twin tube cradle
  • Suspension – 34mm telescopic forks, Twin shock rear
  • Brakes – 275mm disc floating caliper 180mm drum
  • Wheels – 300 x 19 3.50 x 18
  • Weight – 171kgs
  • Top speed – 102mph
  • Wheelbase – 1380mm
  • Fuel capacity – 15 litres

Suzuki GT380 Road Test Gallery

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