Super Commuter: 1973-1977 Suzuki GT185

Comparing the Suzuki GT185 with its main sub-200cc competitors, the Yamaha RD200 and Honda CB175.

Suzuki

1973-1977 Suzuki GT185

Photo courtesy Rizingson Vintage Motorcycles

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Suzuki GT185
Years produced:
1973-1977
Power:
21hp @ 7,500rpm (claimed)
Top speed:
79mph (period test)
Engine:
184cc air-cooled 2-stroke twin
Transmission:
5-speed, chain final drive
Weight/MPG:
280lb (w/half tank fuel)/46mpg (period test)
Price then/now:
$925 (1975)/$500-$1,500

Sales of new motorcycles peaked in the U.S. in 1973, with more than 1.5 million units leaving showrooms — five times the number of bikes sold in 1992 and triple 2015’s figures. And while the sales surge could be attributed to the baby boom, there was another factor at work; the OPEC oil embargo. The price of a barrel spiked from $3 to more than $12, and many stations simply ran out of gas. So it made sense to keep a commuter bike in the garage that you could fill from your lawn mower gas can and would better 45mpg — at least four times a typical gas guzzling auto.

Combining most of the comforts of a bigger bike with small size and nimble performance suiting both experienced riders and newbies alike, the sub-200cc category was suddenly taken seriously.

“Best in its class,” Cycle World wrote of the 1975 Suzuki GT185M Adventurer. Under its “Ram-Air”-cooled cylinder head was a 184cc 2-stroke parallel twin with a four main-bearing crank. The conventional piston-port design used one intake, two transfer and one exhaust port per cylinder. A pair of 20mm Mikuni carburetors fed the cylinders and lubrication was by Suzuki’s CCI (Cylinder Crankcase Injection) system. Helical primary gears drove an 11-plate wet clutch to a 5-speed gearbox. The electrical system was fed by a 12-volt DC generator that also doubled as the starter motor, mounted on the left-side end of the crankshaft. A kickstarter was included as backup.

The powertrain slotted into a single downtube steel tube frame with a telescopic front fork and a rear swingarm controlled by a pair of coil spring-over shocks. Both ends ran on 18-inch wheels, with 2.75-inch front and 3-inch rear tires. First year bikes had a twin-leading-shoe front drum brake, but that was quickly upgraded to a 9.3-inch hydraulic front disc for 1974.

The GT185 came fully equipped with grown-up features including a paired speedometer (with trip) and tachometer, electric start, a lockable seat, a dash-mounted ignition switch and adjustable rear shocks. Cycle Guide tested the 1975 GT185M, enjoying the “docile power characteristics that make it easy to ride, even for first timers,” and finding that the engine wasn’t peaky, but delivered “a smooth, constant flow of power throughout the rev range.” That said, the engine needed to be kept spinning: “… open the throttle wide below 3,500rpm in the upper two gears, the engine bogs out.” And while the GT185 was quite capable of reaching highway speeds: “It takes a little more time … but once you get there it moves along effortlessly.”

Testers decided the GT185 was quite comfortable, though perhaps a little compact for 6-foot-plus riders. Cycle Guide found the “overall gear ratios well suited … the clutch and gearbox worked perfectly,” with none of their testers reporting missing a single shift. Around town, they reported, the GT185 “flicks around corners quickly and predictably,” and noted its stability even over rain grooves.

But when pushed hard, the little Suzuki showed its handling limitations. Both Cycle Guide and Cycle World decided this was the GT’s major shortcoming, down to a combination of limp shocks and fork legs that were both softly sprung and under-damped. Combined with just 3.75-inch front and 3-inch travel rear, problems soon arose when the 185 was cornered hard. “The rear end pitches and wallows severely at the same time that the front suspension is pogoing,” Cycle World wrote, concluding, “You could get into big trouble before you knew it.”

The limited suspension travel also affected braking: “In a panic stop, the front end takes a big nosedive … the forks easily bottom out … and the front wheel wants to turn off course,” wrote Cycle Guide. Upgraded suspension was recommended: “With just that one change, the GT185 could very well end up being the best thing in its class.”

Overall though, Cycle magazine said, “The Suzuki 185 is an impressive machine: a refined, smooth, civil piece of hardware with nary a ragged edge.” Ultimately, the GT185’s biggest challenge came not in its own capacity class, but from the new “econo” 350s and 400s, like Honda’s CJ360T, selling at 200cc-class prices. By 1978, the GT185 was gone. MC


Contenders: Sub-200cc commuter rivals to Suzuki’s GT185

1974-1975 Yamaha RD200
Years produced:
1974-1975
Power:
18.7hp @ 9,000rpm/84mph
Engine:
195cc air cooled 2-stroke parallel twin
Transmission:
5-speed, chain final drive
Weight/MPG:
290lb (curb)/35-45mpg
Price then/now:
$995 (1975)/$600-$2,000

Inside Yamaha’s 195cc 180-degree 2-stroke twin was a four-main-bearing crankshaft with needle roller small- and big-end bearings. Lubrication was by Yamaha’s Autolube system, and fueling by a pair of 20mm Teikei carburetors via 4-petal reed valves. Helical primary gears drove a wet clutch and 5-speed gearbox. Electrics included a combined 12-volt DC generator/starter motor unit, though the kickstarter was retained.

The power unit was suspended from a single-downtube spine frame with a conventional telescopic front fork and rear swingarm. Tires were 3 x 18-inch rear and 2.75 x 18-inch front with a 7-inch twin-leading-shoe front drum brake and 5.9-inch single-leading-shoe rear drum. Testers found the power to come on strong above 4,500rpm, but with little below that — in spite of Yamaha’s “Torque Induction” reed-valve system. Slipping the clutch was usually necessary for a clean getaway and testers were divided on the RD200’s handling, Cycle Guide finding it “very good for such a small motorcycle,” while Cycle criticized “suspension surging,” and “oscillation.” They criticized the powerful but insensitive front brake, finding the bike difficult to control under hard braking.

For a commuter bike the main issue was fuel consumption, which averaged roughly 37mpg, giving a range of just 100 miles. OK, but hardly stellar.

1969-1973 Honda CB175
Years produced:
1969-1973
Power:
20hp @ 10,000rpm/76mph
Engine:
175cc air-cooled SOHC parallel twin
Transmission:
5-speed, chain final drive
Weight/MPG:
297lb (w/half tank fuel)/40-50mpg
Price then/now:
$894 (1972)/$500-$2,500

The first CB175 was the K0 of 1968 (based on the CB160), redesigned into the 1969 K3 with a new frame, a more upright engine and revised styling.

The 360-degree twin’s built-up crank ran on a roller bearing big end and four main bearings, with a central chain spinning the single overhead camshaft. Drive to the 5-speed gearbox was by paired straight-cut gears with staggered teeth (to control lash) and a wet clutch. Starting was electric, with a kickstarter as backup.

A new frame with a pressed steel spine, single downtube and dual lower rails cradled the powertrain and swingarm, suspended by dual rear shocks and standard telescopic front forks.

Brakes were a 6.25-inch twin-leading-shoe drum front and a 5.5-inch single-leading-shoe rear running on 18-inch wheels fitted with 2.75-inch and 3-inch tires, respectively. A paired tachometer and speedometer, a revised gas tank and new bodywork completed the makeover.

Cycle Guide’s tester found the CB175 to be “remarkably free of legitimate criticism,” noting, “While it’s not a big road burner” performance was adequate, and handling and braking were, “absolute tops.” The Honda was most at home in traffic, making it an ideal machine for commuting.