1973-1977 Suzuki GT250

Tomorrow’s Classics: 1973-1977 Suzuki GT250, a 247cc parallel twin 2-stroke.

| November/December 2013

Suzuki GT 250
Claimed power:
31hp @ 7,500rpm (see text)
Top speed: 91mph (period test)
Engine: 247cc air-cooled piston-port 2-stroke parallel twin
Weight: 320lb (dry)
Price then/now: $810 (1973)/$1,500-$2,500

By the 1970s, as motorcycles grew cylinders and cubic centimeters, welterweight 250cc bikes were increasingly viewed as a transition class as many new riders moved up the capacity ladder to a “real” motorcycle. And that’s a shame, because the enduring charms of many frisky lightweights have become overlooked.

Take the Suzuki GT250 for instance. Developed from the potent and petulant T20 X6 Hustler (also called the Super Six) and the T250 Hustler of 1969-1972, the GT250 matured over its life from a wild child with a penchant for perforating pistons into a mild-mannered sophisticate. Along the way, it lost its performance edge to increasingly restrictive noise and emissions regulations (measured rear wheel horsepower went from 22.3 at 7,500rpm for the 1973 GT250K to just 20.1 for the 1975 GT250M), yet it arguably became a better all-around motorcycle as it matured.

Suzuki’s basic formula was well tried and tested. The 247cc parallel twin 2-stroke used conventional piston porting with two transfer ports and was fed by two 26mm carburetors. The crankshaft ran on three main bearings and drove the 6-speed transmission through a gear primary with wet multiplate clutch and chain final drive. The powertrain fitted into a duplex cradle frame with a twin shock rear swingarm and conventional telescopic fork. Suzuki’s Posi-Force oil injection system took care of engine lubrication from a 1-quart oil tank.

Launched in Japan in 1970, the GT250 arrived in North America for the 1973 season as the GT250K, claiming 31 horsepower, a dry weight of 320 pounds and a top speed of 90mph. New for that year (1972 in Japan) was a front disc brake and Suzuki’s “RAS” Ram Air System — an aluminum plate bolted to the top of the engine intended to direct cooling air onto the cylinder heads. It also helped to make the engine a bit quieter. Styling was revised from the previous year’s Japanese market model, with sharper lines and a new paint scheme.

In addition to helping the 2-stroke twin run cool, the Ram Air System also obscured the rubber inserts between the cooling fins designed to reduce “ringing.” More restrictive carburetor slides and exhaust also reduced overall engine noise, but resulted in a drop in power over the earlier (Japan only) GT250. This same basic specification (but with declining power output, as noted) continued through the 1975 GT250M, but a revised engine arrived for 1976 (GT250A) with four main bearings, four transfer ports and 28mm carburetors in place of the previous 26mm units. The Ram Air System was dropped at the same time, although fin area on the cylinder head was increased to ensure effective cooling. Although it continued in some markets, the GT250 was dropped in the U.S. in favor of Suzuki’s growing line of 4-stroke twins and triples.

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