SHATTERING ACCELERATION-121 M.P.H. Suzuki water-cooled G.T. 750 is a superb sports roadster

Press, Volume CXI, Issue 32779, 2 December 1971, Page 12

SHATTERING ACCELERATION-121 M.P.H. Suzuki water-cooled G.T. 750 is a superb sports roadster

(By

R. O. DEW)

TT is slightly more than a year since the Japanese Suzuki factory stunned the motor-cycle industry with the unannounced appearance at the Tokyo Show of the world’s first watercooled three-cylinder 750 c.c. two-stroke in prototype form.

Few specifications were available at the time but it was then clearly the most complex super-sporting roadster ever built. It was so advanced in its concept that many motoring journalists were convinced that it was no more than the result of a design exercise never intended for full production.

However, they were wrong. The machine, known as the Suzuki G.T. 750, is now in full production and the demand is so great that the factory has no hope of meeting the market requirements. The first two examples of this tremendously exciting mount have now arrived in New Zealand. One has gone to Auckland; the other is on display in Christchurch. The reaction here has been just as overwhelming as it has been everywhere else in the world.

The machine on display in Christchurch was loaned to “The Press” by Scooter, Motor-cycle and Moped Services, Ltd, for testing last week and for this correspondent it was an unforgettable experience. Sure-footed at speed over the most rutted tarmac, it whistled over the Banks Peninsula hills as if they were not. there. On the flat it gobbled up the miles in effortless fashion.

At first sight, the G.T. 750 appeared rather bigger, and at 5171 b, heavier than expected. But it was so

finely balanced and the riding position so comfortable that it could be manoevred with ease at low speeds in heavy traffic.

This might sound rather dull but this machine is nothing if it is not stimulating. It is truly an exceptional piece qf machinery with a turn of speed which would make many road racing motor-cycles appear rather 1 pedestrian. However, the gearing seems to be chosen for acceleration rather than top speed. Peak power of 67 brake horsepower comes in at 6500 revolutions per minute and the engine revs easily to 7500, although the counter is red-lined at 7000. At 7500 r.p.m., speeds of 38, 64, 82 and 99 miles an hour can be obtained from the first four gears. The same engine speed in top gear is equivalent to 121 miles, an hour. With a higher gearing, the theoretical top speed of the machine would be round the 150 m.p-h. mark. The

speedometer certainly caters for speeds of this nature. It is calibrated to 160 m.p.h. On test, the engine’s smoothness, quietness and widely spread torque combined to disguise the briskness of the acceleration, which is actually superior to that of the Honda 750 c.c. four.. The G.T. 750 is essentially a touring machine in its present form. There can nevertheless, be little doubt that it will perform well on the race track. At least one Christchurch road racer, M. Gibbons, has plans to con-

vert one into a facing machine, an experiment which will be watched with interest now that the F.LM. has agreed to recognise a 750 c.c. class.

The engine itself is a masterpiece. With the water jacket helping to absorb any vibrations, it runs rather like a turbine. But its most impressive feature is its power band. This seems to begin at idling revolutions and is. still there at the red-lined 7000 mark on the revolution counter. For a two-stroke, this is quite incredible. Adding to the feeling of complete luxury, the engine is mounted on rubber.

The actual capacity of the engine is 738 c.c. Maximum torque is reached at 5500 r.p.m., although it is possible to rocket away from standing start with the engine turning over at less than 3000 r.p.m. Riding is so effortless that considerable willpower and concentration is needed to keep below the legal speed limits. When it is considered that

30 m.p.h. can be exceeded with ease in bottom gear, this can be readily appreciated. During the early stages of testing, I was convinced that the speedometer was recording kilometres per hour. I soon realised my mistake as the traffic disappeared behind. The wide spread of power has been obtained by basing the engine porting on knowledge gained in developing Joel Roberts’s world championship - winning moto-cross model. The excessive thirst which bedevils so many high performance two-strokes has been overcome. Figures of 85 miles per gallon at 37 m.p.h. and 62 miles per gallon for normal riding have been obtained in overseas tests. \

The manufacturers also claim to have eliminated the traditional blue haze, which most two-strokes produce from their exhausts, by precise control of mixture and oil-pump output. The exhaust gases from the four pipes on the test model were certainly invisible. « One of the most sophisticated features of the machine is the cooling system. The water is circulated by an impeller in the bottom of the crankcase and the four stages of operation are automatically controlled by a thermostat.

The first stage is for rapid warming up. The thermostat blanks off the outlet to the radiator and the water returns to the impeller through a by-pass. When the water temperature reaches 82deg centigrade, the thermostat opens the outlet to the radiator without closing the by-pass. At 95deg the by-pass is closed. If the water temperature reaches 105 deg, a four-blade electric fan is automatically switched on. The capacity of the system is a gallon. The only criticisms which could be made of this ma-chine—-andthey are both

minor—involve the gearbox and the brakes. The fivespeed transmission on the test model was a little clunky and a hydraulic disc

brake at the front would be an improvement. The four-leading shoe unit fitted was adequate without being outstanding. In standard form, the Suzuki is fitted with an electric starter as well as the normal kick lever. The engine fired easily using both systems. Twin speedometer and revolution counter units are fitted with an engine temperature gauge on top. There are turning indicators, a kill button, twin mirrors and a passenger grab rail. The tail light is operated by the front brake as well as the rear. Engine lubrication is automatic. The retail price in New Zealand will be $1789, which is good value by today’s standards for what is a leader in its class. However, it might be some time before there are enough to go round. A shipment of 18 are expected in Christchurch this month and the majority are already ordered. SPECIFICATIONS: Engine, two-stroke water-cooled threecylinder; displacement, 738 c.c.; bore and stroke. 70 x 64mm.; compression. 6.7 to 1; maximum power, 67 b.h.p. at 6500 r.p.m.; maximum torque, 7.7 kiiog. at 5500 r.p.m.; lubrication, automatic; brakes, 1 double leading shoe at front and single leading shoe at» rear; transmission, five-speed gearbox.