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Suzuki GT125 Road Test

Suzuki GT 1251977 Suzuki GT125

Motorcyclist Illustrated Dec 1977

There cannot be many motorcyclists who commute to work each day at a steady 9000rpm, but this is the rather rare experience that faces owners of the Suzuki GT125 who wish to keep up with the traffic on dual carriageways and motorways. For at 9000rpm this perky little two-stroke twin is singing along at 70mph, with another l000rpm in hand before reaching the red line.

One of the outstanding attributes of the GT125 is its ability to deliver this kind of performance for mile after mile without overheating ok

showing the slightest sign of power loss. It will maintain the legal limit unstintingly on a level road and exceed it by at least 5mph in favourable conditions, but naturally a steep gradient usually requires changing down from fifth to third gear to preserve momentum.

Cruising at this sort of speed the Suzuki is commendably smooth, the only vibration being felt as a tingle through the footrests which is definitely present but never bothersome. The tank, seat, and handlebar are free from the malady, and the rubber-mounted mirrors stay clear also. The mechanical noise is low for a two-stroke, helped perhaps by the cast aluminium Ram Air shroud over the cylinder head. Initially the combined induction roar and exhaust noise was noticeable, but the exhaust emits one of the more pleasant two-stroke sounds and is nowhere near as pronounced as the wail emanating from its 250cc brother.

The price you pay for this level of performance is heavy fuel consumption. The average for the test was 40mpg — the same as the Suzuki GT250, the Honda Gold

Wing and CB750 K7. Throughout the test I rode the machine close to its performance limit, because this was the only way to keep to my time schedules. It was also the most fun and the Suzuki thrived on this treatment. Riders who are not prepared to accept this sort of fuel consumption would be advised to steer clear of the GT125, because it would be pointless spending money on a high-performance machine in its class and then pottering around everywhere in a bid to conserve fuel. If it's economy you're after you would be far better advised to buy one of the four-strokes or the smaller step-throughs.

The main drawback of the high petrol consumption, other than the sheer cost, is that the machine's 2.2 gallon petrol tank will take you a mere 75 miles before you need to start searching out a petrol station. The Suzuki went 12 miles on reserve before I stopped to replenish its tank, which took exactly two gallons to fill to the brim. If the manufacturer's tank capacity claim is correct that means reserve will take you no more than 20 miles before leaving you stranded. The Suzuki is not alone in having too small a tank, but an extra half gallon at least would be welcome - preferably a gallon.

The other reason for the high fuel consumption is the quite amazing acceleration offered b/ this 2531b lightweight. Power starts to come in at around 4000rpm. It climbs gradually to 6000 where it grows stronger. By 7000rpm the bike starts to wail and goes hurtling forward with incredible rapidity for a 125, with the power rising progressively to 9500 and falling off imperceptibly thereafter. Between 7000 and l0,000rpm the GT125 must be one of the quickest machines around under 200cc, and the bewitching effect of its acceleration in this area is such that I could hardly resist using the revs freely. This characteristic makes the little Suzuki great fun to ride, and it will have even greater appeal to riders who don't have my 14 stone carcass to lug around.

One of the equally appealing traits of the GT125 is that, unlike its 250cc stablemate, it can be eased away from a standstill on a gentle throttle without having to be kept within a narrow power band, and therefore I would consider it a suitable machine for beginners. It has the benefit of lower initial cost than most 250s, and lower insurance rates, yet is able to deliver usable performance as the novice becomes more proficient. And if the rider has his sights set on bigger machinery, then he can look forward to passing the test on the 125 and move on to greater things, skipping the expensive 250 class entirely.

The engine is a straightforward four-port two-stroke twin, producing 16bhp at 9500rpm and 9.4 ft-lbs of torque at 9000rpm. The five gears are driven through a wet multiplate clutch and are ideally spaced. No matter what the situation there is always a correct gear to cope, and the changes are smooth, silent and positive. Actual top speed is 75mph at l0,000rpm, with 78mph indicated on the speedometer; at an indicated 60mph the true speed is 56.2mph. The motor is willing to rev beyond 10,000 in top gear on hills, but this will only contribute to more rapid component wear and possible damage. Oil is metered to the engine by the successful Suzuki CCI injection system, which is reasonably economical at 200 miles to a pint of two-stroke lube.

Starting was always a single-kick task, hot or cold and the carb-mounted choke could be dispensed with quickly after firing. The twin-coil ignition proved reliable and the test bike never lost its tune despite prolonged hard use. Clutch lever action is featherlight, and the light steering makes for easy manoeuvrability in traffic.

Far more surprising is the Suzuki's excellent straightline stability right up to its top speed. Roadholding is very good and the suspension copes well with fast, smooth bends. On bumpy backroads, however, the handling was much less precise but still enabled spirited riding in relative safety. The lurching and wallowing I experienced on bumpy bends may have been due largely to my weight, but the frame certainly seems well able to handle the power the engine puts out

A single downtube from the steering head is welded to a duplex cradle running beneath the motor to meet the swinging arm. Three tubes run back from the top of the steering head, the main one bending down to tie up with the swinging arm pivot, the other two continuing back to form the top part of the triangulated rear subframe. It looks good and works well. Coupled with adequate ground clearance this allows the GT125 to be thrown about with ease, although I have my doubts about the suitability of the Inoue tyres. They never felt quite right, yet even in wet weather they held the road and showed no signs of imminent breakaway.

Inspiring less confidence are the brakes. They work well in dry weather, but in the wet that hydraulic front disc suffers from an unacceptable delayed action. A sticker on the fork leg warns riders of this well-known trait, but all the stickers in the world are no substitute for some serious and much-needed'development of brake pad materials. As mentioned in my Gold Wing test, work by the Transport and Road Research Laboratory indicates that pad material may have more bearing on this wet braking problem than actual disc material, as hitherto assumed. Whatever the cause, remember that in wet weather the first two seconds of front brake application bring no results while the pads dry out; after that the brake works normally - until the next time.

Lighting on the GT125 is surprisingly good for such a small unit, and both beams give a useful spread of light. The tail light is very large and bright and the indicators are easily visible in daylight.

Instrumentation is simple, and thankfully we are spared Suzuki's digital gear indicator on this model. The matching speedometer and revcounter are well-lit, and the speedo contains a trip odometer while the neutral, high beam, and indicator warning lights are housed in the tachometer.

The small 12y battery, main electrical connections and a spare fuse live behind the right snap-on sidepanel. The oil tank and tool tray are easily accessible under the hinged and lockable dualseat, which incorporates a helmet lock and the petrol tank is quickly detachable for easy access to the ignition coils. The air filter element is easy to reach from the left side of the engine, and the machine boasts a simple steering lock that requires a minimum of fumbling.

The saddle is reasonably comfortable, but a pillion rider might soon tire of the constant rise and fall of the rear footrests, mounted directly on the swinging arm. While we are discussing that general area of the machine, I fail to appreciate why Suzuki cannot fit a full chain enclosure. The present chain guard simply does not keep chain oil off the rear of the bike and after a few hundred miles this can detract greatly from the otherwise neat appearance. The standard of finish is good, however, and both paint and chrome look durable.

The GT125 boasts an excellent . horn for a motorcycle of this, capacity, and the large rear light is an added safety bonus. All the more pity, therefore, that the brake light is operated only by the rear brake; there is provision for a front brake light to be fitted but, like the 250 and 400cc Suzukis, none is. It would offer an important safety boost, and this would more than outweigh the small extra cost involved. Cost, again, is probably the reason why the automatic vacuum fuel taps fitted to most larger Suzukis are absent from the GT125. The manual tap fitted to the test machine was stiff and therefore awkward Jo use.

In town the Suzuki's light steering and short wheelbase make it an ideal choice for threading through tire­some snarl-ups, and that extra urge from the motor at 7000rpm is especi- ally useful for passing slower traffic as quickly and safely as possible on a 125. And when it come to parking, the machine's light weight takes the effort out of using the centre stand, while a side stand is fitted to meet the needs of the really lazy.

Suzuki's GT125 will set you back £460, serving as a horrifying reminder of what inflation is doing to the price of even small motorcycles. But it still represents good value, and slightly undercuts the competition: Yamaha's RD125 is listed at £475 and Honda's new CB125T at £489. Model for model, Suzuki appear to have a policy of pricing their machines just below those of their rivals, and this certainly seems to pay off, judging by the popularity of the smafler models especially. But the GT125 gives more than simple value for money — it adds a tinge of the performance and excitement of larger bikes to the commuter class. Young riders looking for a replacement for that cast-off moped would be wise to consider seriously a quick 125 such as this Suzuki before rushing off to spend almost half as much again on a 250.

Suzuki GT125 Specifications;

  • Engine: Two-stroke four-port with Ram Air cooling Displacement: 124cc Bore and stroke: 43 x 43mm
  • Lubrication: Suzuki CCI
  • Oil tank capacity: 2.1 pints (1.2 litres)
  • Transmission: Five-speed constant mesh
  • Maximum power: 16 bhp at 9500rpm
  • Maximum torque: 9.4 ft-lbs at 9000rpm
  • Fuel tank capacity: 2.2 gals (10 litres)
  • Fuel consumption: 40mpg average on 2 star
  • Oil consumption: 200mpp
  • Overall length: 75.2in
  • Width: 30.3in
  • Overall height: 41.9in
  • Ground clearance: 5.Sin
  • Suspension: Telescopic oil-damped fork front; oil-damped five-way-adjustable shocks rear
  • Tyres: 3.00 x 18 rear Inoue 2.75x18 front
  • Dry weight: 2381bs
  • Starting: Kickstart only
  • Top speed: 75mph at 10,000rpm (maximum safe revs)
  • Speedometer error: True 56.2mph at indicated 60mph
  • Colours: Red, candy gold, metallic blue
  • Final drive: Exposed unlubricated chain
  • Brakes: Single-leading-shoe drum rear; single hydraulic disc front
  • Ignition: 12v battery and twin coils
  • Frame: Single-downtube tubular cradle-type
  • Price new: £460

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