The Suzuki GT250, also known as the Suzuki Hustler in the US is a ,

two-stroke A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a power cycle with two strokes (up and down movements) of the piston during one power cycle, this power cycle being completed in one revolution of ...

, twin-cylinder motorcycle produced by the Japanese

Suzuki is a Japan, Japanese multinational corporation headquartered in Minami-ku, Hamamatsu, Japan. Suzuki manufactures automobiles, motorcycles, All-terrain vehicle, all-terrain vehicles (ATVs), outboard motor, outboard marine engines, wheelchairs ...

company between 1971 and 1981. The model was developed from the earlier T250, and was one of the best selling motorcycles in its class. For 1978 the bike was redesign and marketed as the GT250 X7. The X7 was capable of reaching in favourable conditions. The model range was discontinued in 1981 in favour of Suzuki's

four stroke A four-stroke (also four-cycle) engine is an internal combustion (IC) engine in which the piston completes four separate strokes while turning the crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either directi ...

models, and the X7 was developed into the

RG250 Gamma The Suzuki RG250 Gamma was a two-cylinder parallel, water-cooled 250 cc two-stroke motorcycle produced by Suzuki from 1983 to 1987. One of the major features of the RG250 Gamma was its large power-to-weight ratio. Able to produce up to 45 ...

Technical details

Engine and transmission

The T250's engine was a development of the earlier T20, which had been introduced in 1966. The 180° piston ported two stroke twin was of

unit construction : ''For the vehicle design where the vehicle's skin is used as a load-bearing element, see Monocoque.'' Unit construction is the design of larger motorcycles where the engine and gearbox components share a single casing. This sometimes includes ...

and had alloy

head A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple animals may ...

and alloy

barrels A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden staves and bound by wooden or metal hoops. The word vat is often used for large containers for liquids, u ...

with cast iron liners. Bore and

stroke A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functionin ...

were and the claimed power output was @ 7,000 rpm. In 1971 the ''Ram Air System'' cooling duct, as used on the GT380 and GT550, was added to the cylinder head. It is debated whether the Ram Air System improved cooling significantly or was a cosmetic addition. In 1976 the engine was revised; the

main bearing Main may refer to: Geography * Main River (disambiguation) **Most commonly the Main (river) in Germany * Main, Iran, a village in Fars Province *"Spanish Main", the Caribbean coasts of mainland Spanish territories in the 16th and 17th centuries ...

s were increased in number from three to four and two extra transfer port added, increasing power to @ 7,500 rpm. The ram air was removed and the fins on the head enlarged to compensate. A new engine was designed for the 1978 X7 model. Whilst retaining the 54 mm bore and stroke, the engine was more compact and weighed less than the GT250C engine. The new engine used Suzuki's dual induction system, first used on its off-road bikes. The system used both piston porting and

reed valve Reed valves are a type of check valve which restrict the flow of fluids to a single direction, opening and closing under changing pressure on each face. Modern versions often consist of flexible metal or composite materials (fiberglass or carbon f ...

s, which gave better response through the rev range.

Ignition Ignition may refer to: Science and technology * Firelighting, the human act of creating a fire for warmth, cooking and other uses * Combustion, an exothermic chemical reaction between a fuel and an oxidant * Fusion ignition, the point at which a ...

was by twin coils with points mounted on the end of the

crankshaft A crankshaft is a mechanical component used in a piston engine to convert the reciprocating motion into rotational motion. The crankshaft is a rotating shaft containing one or more crankpins, that are driven by the pistons via the connecting ...

. Fuel was delivered by twin 26 mm Mikuni

carburettors A carburetor (also spelled carburettor) is a device used by an internal combustion engine to control and mix air and fuel entering the engine. The primary method of adding fuel to the intake air is through the venturi tube in the main meterin ...

, which had restrictive slides to reduce intake noise. The carbs were increased to 28 mm in 1975 and were rubber mounted. The carbs were reduced to 26 mm on the X7 to increase mid-range power. The engine was lubricated by Suzuki's ''CCI'' system. Primary drive was by helical gears to a multi-plate wet clutch. The six speed gearbox received revised second and third gear ratios in 1976.

Chain drive Chain drive is a way of transmitting mechanical power from one place to another. It is often used to convey power to the wheels of a vehicle, particularly bicycles and motorcycles. It is also used in a wide variety of machines besides vehicles. ...

took power to the rear wheel.

Cycle parts

The duplex cradle frame of the T250 was modified for the GT250 with three small top tubes instead of the previous single large tube. Rear suspension was by swinging arm with twin

shock absorber A shock absorber or damper is a mechanical or hydraulic device designed to absorb and damp shock impulses. It does this by converting the kinetic energy of the shock into another form of energy (typically heat) which is then dissipated. Most sh ...

s. At the front

telescopic fork A telescopic fork is a form of motorcycle front suspension whose use is so common that it is virtually universal. The telescopic fork uses fork tubes and sliders which contain the springs and dampers. The main advantages of the telescopic fork ...

s were used. A new single downtube frame was designed for the X7, which saved over the previous frame. Initially brakes were

drums A drum kit (also called a drum set, trap set, or simply drums) is a collection of drums, cymbals, and other Percussion instrument, auxiliary percussion instruments set up to be played by one person. The player (drummer) typically holds a pair o ...

front and rear, the front being an effective 2ls item. The front brake was replaced in 1972 with a single disc, which suffered poor wet weather performance.

Model variants

The first of the GT250 models was introduced to the Japanese home market in 1971 and apart from some cosmetic changes was identical to the T250. The Ram Air System and disc frame brake were added in 1972. In 1973 the model was introduced to export markets.

GT250

Introduced to the Japanese domestic market only in 1971, the model was based the T250 and had styling similar to the T350.

GT250 II

Still only for the Japanese market, the 1972 GT250 II gained a disc front brake, gaiter on the front forks and Suzuki's Ram Air system.

GT250K/L/M

In 1973 the bike was restyled and released in Europe and America in 1973 as the GT250K. The exhausts were modified to comply with noise and emission regulations which reduced power. It was available in red or green with a white stripe. The 1974 L and 1975 M models had minor cosmetic changes only.

GT250A/B/C

An updated engine was introduced in 1976 with a 4 bearing

, 2 extra transfer ports and larger carbs which increased power. The Ram Air System was removed. Although the GT250A faster than the previous model, it suffered from lack of power below 4,000 rpm. In the UK the model was heavily advertised with the then 500cc world champion

Barry Sheene Barry Steven Frank Sheene (11 September 1950 – 10 March 2003) was a British professional motorcycle racer. He competed in Grand Prix motorcycle racing Grand Prix motorcycle racing is the premier class of motorcycle road racing even ...

heading the campaign. The GT250 became the top selling 250 cc bike, the learner class at the time. The 1977 B and 1978 C models only differed by minor cosmetic changes.

GT250 X7

The bike was redesigned for the 1978 X7 (known as the X7E in Germany and RG250 in Japan). The bike was lighter than the GT250C and more compact. Although producing no more power than previous models, the new engine was more tractable. The lighter and more compact X7 was capable of under favourable conditions. The X7 continued in production until 1981 and formed the basis of the RG250 Gamma.

References

External links

* * * {{Suzuki T & GT series timeline, state=autocollapse GT250 Motorcycles introduced in 1971 Two-stroke motorcycles Motorcycles powered by straight-twin engines