Back in the early ’70s Suzuki was looking into the inevitable future and concentrating on getting into the four-stroke market, while still making good money from its two-strokes. And the predecessors of this GT250 Hustler had helped a lot.
Its parallel twin engine, perfectly square at 54 x 54mm bore and stroke, had first seen the light of the showroom floor in 1965 as the X-6 Hustler, a 250 tiger, which astounded the American motorcycling mind with a 90-plus-mph top speed and six-speed transmission. The engine was a simple piston-port design, with new-fangled automatic oiling, and cylinders were aluminum with iron liners.
Move forward eight years, and the rather similar GT250 Hustler appears—but with Suzuki’s Ram Air System (RAS) bolted to the top of the engine. The rubber-mounted hood was first seen on the company’s 1972 triples, the GT380 Sebring and GT550 Indy, which was the beginning of the Grand Touring series. The approach was simple enough, with this rather angular shroud aiding the cooling of the triple’s middle cylinder, sending more air through the cooling fins.
On a parallel twin this was more problematic, but useful in keeping the noise down. Two-strokes from the ’60s were notoriously rackety, especially in warm-up mode, and prone to give out a ringing and pinging sound from the fins. Strips of heat-resistant rubber were used in the 250’s cylinder-head fins to reduce the noise. All very civilized.
RAS was also a sales gimmick, giving the previous T250 model a new look. The factory was claiming the GT twin developed 31 horses at 7,000 rpm, but “Cycle” magazine used a rear-wheel dyno to measure the 1973 model’s horsepower: 22 at 7,500 rpm. The same magazine got a mere 20 horses when testing the similar 1975 version. As the humorist types back then liked to say, Suzuki was measuring power at the top of the piston.
It is true that Suzuki with this GT version had knowingly cut back on the power. This was because a major effort had been made, wise or not, to give the touring rider a quieter ride. However, it took some bright light to take the 26mm Mikuni carburetors apart and measure the slides; they had been lengthened by 6mm, which meant that full throttle was an impossibility. Two-strokes made a lot of noise from the intakes, so Suzuki used the longer slides on the GT–hence the slightly quieter engine. When found out, Suzuki immediately switched to correctly sized slides.
A battery and coil supplied the sparks, and the battery was a mere five amp/hour. Americans were coming to accept the electric leg, but because of weight and costs, no such starter was on the GT250. The rider’s left leg provided the starting mechanism, not that pushing the left-side kickstarter was much of a problem.
The engine was Suzuki solid, with the crankshaft running on three ball bearings, the one-piece connecting rods having needle bearings both top and bottom. Gasoline passed into the crankcase via that pair of Mikunis, while lubrication was done by the improved CCI (Crankcase Cylinder Injection) automatic-oiling arrangement. Just to make sure that the end bearings on the crankshaft were properly taken care of, they were pressure fed using CCI’s multipoint injection system. Compression ratio was an acceptable 7.5:1. The oil tank, part of the right side cover, held 2.8 pints and had a little window to alert the rider when oil was getting low.
Helical gears sent power rearward to a multi-disc wet clutch and then through the tranny, with its own oil supply. Sixth gear was very much an overdrive, which helped reduce noise at touring speeds.
Frame was a double cradle, with a major change from its T250 predecessor found under the four-gallon gas tank; instead of one large beam, there were now a trio of smaller tubes, strengthening the chassis and allowing for a more positive feel in the corners. The frame extended under the seat, so there was no bolt-on addition. Since this had touring pretensions, wheelbase was extended almost an inch to 52 inches for better high-speed stability.
The telescopic fork was adequate, as were the pair of adjustable shocks on the swingarm. Both wheels were 18-inchers, carrying a 3.00 tire on the front, 3.50 on the back. Front brake was a competent single disc, with a drum at the back that was activated hydraulically. Above the headlight were a speedo and tachometer. Wet weight was a hefty 350 pounds, 50 more than the original X-6.
The GT designation did not really live up to the bike’s touring abilities. As a solo bike, it was OK in the quarter-liter category, but with a passenger on board taking off from a stop was both a bit slow and noisy. If the engine was pulling less than four grand, a stall was quite possible, and quiet departures were not to be had. Plus the seat height of 31 inches meant a relatively tall rider was probable, leaving not much room for a passenger. The saddle was narrowed at the front, for those with challenging inseams, but not very comfortable for the rider when carrying a passenger.
In the end the GT250 Hustler, now a pussycat, only lasted three years. The RAS was removed, and the bike became simply the GT250 for the next two years–with bigger fins in the head to aid in cooling. That Ram Air System apparently served mainly to slow things down.
This 1975 model seen in the photos, in Aztec Yellow, spent much of its life in boxes and was only recently put back together–the only thing missing being the left side cover, which comes from a different year.