GT550 ENGINE STRIP

It might not be fiery, but Suzuki’s two-stroke triple is torquey and reliable

Suzuki’s triple in lots of little bits

Three-cylinder models were added to Suzuki’s alltwo-stroke range for 1972. Following the launch of the unorthodox water-cooled GT750 flagship came the air-cooled GT380 and GT500, also of unusual appearance thanks to their engines’ shrouded Ram Air cylinder heads. While Suzuki developed a racer version of the biggest triple, the smaller bikes’ oddball capacities signalled that they were not aimed at track classes. GT stood for Grand Tourer and while the 543cc GT550 engine featured here can develop a healthy 50bhp, its main virtues are smoothness, tractability and general civility rather than shattering performance. The foursilencer exhaust system, with the centre downpipe dividing into two, makes a pleasant humming sound.

The GT engines were not Suzuki’s first two-stroke triples. Hamamatsu’s little Fronte cars and vans introduced in the mid1960s had inline three-cylinder engines with fan-assisted air cooling, in versions from 360cc up to 800cc. They followed threecylinder DKW, Excelsior-berkeley and Saab car engines that exploited the favourable harmonics created in a two-stroke triple. However, Suzuki’s motorcycle triples were directly evolved from the successful 493cc T500 twin unit, a design introduced for 1968 and sold alongside the GT550 until 1977, when both models were dropped as Suzuki moved to four-stroke engines.

The GT550 engine changed little during production. The biggest alteration was the adoption of hard-plated cylinder bores and modified porting from 1975, changes not applied to North American market models. The bores are in three separate barrel castings, with most of the fin area at the front and air able to pass between them to aid cooling. Their base flanges are fixed to the crankcase by studs – four per barrel – with longer studs to pass