1978 Kawasaki Z1R-TC: Turbo Power

Enlarge Image Image Gallery The appeal of turbo power launched a brace of unlikely motorcycles, as well, including the Honda CX500/650 Turbo, the Kawasaki GPz750 Turbo, the Yamaha XJ650 Seca Turbo and Suzuki’s XN85. Almost forgotten in the rush was the first turbo bike, the 1978 Kawasaki Z1R-TC. Photo By Corey Levenson

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1978 Kawasaki Z1R-TC
Claimed power: 130hp @ 8,500rpm
Top speed: 135mph (period test)
Engine: 1,016cc air-cooled turbocharged DOHC inline four, 70mm x 66mm bore and stroke, 8.7:1 compression ratio
Weight (wet): 560lb (255kg)
Fuel capacity/MPG: 3.4gal (12.9ltr)/35-45mpg (est.)
Price then/now: $4,995/$12,000-$18,000

Notoriously reticent about horsepower figures, the Rolls-Royce company adopted a snooty retort to inquiries about the output of its automobile engines: “Sufficient,” was all they would say. But when the pavement-bending Bentley Mulsanne Turbo first rolled out of the Derby Works in 1982, the stock answer would no longer do. It became: “Sufficient — plus 50 percent.”

The 50 percent came from a Garrett AiResearch turbocharger bolted on to R-R’s 412ci V8. The prestige car maker wasn’t alone in its approach to instant horsepower, and the 1980s became the turbo decade. Saab, Volvo and others adopted turbos to pep up their 4-cylinder engines, and many American automakers used turbocharged V6s to replace gas-guzzling V8s as a way of meeting fuel consumption targets.

The appeal of turbo power launched a brace of unlikely motorcycles as well, including the Honda CX500/650 Turbo, the Kawasaki GPz750 Turbo, the Yamaha XJ650 Seca Turbo and Suzuki’s XN85. Almost forgotten in the rush was the first turbo bike, the 1978 Kawasaki Z1R-TC.

Boost

The first widespread use of turbochargers was to boost the performance of high-altitude World War II aircraft like the B-17 Flying Fortress and the P-38 Lightning and P-47 Thunderbolt fighters. In 1978, Kawasaki’s flagship 1,000cc model needed a boost. The 1970s had become a game-changing decade in motorcycle development, and Kawasaki was being left behind. In spite of leapfrogging Honda’s CB750 with the double overhead cam 903cc Z1, Kawasaki’s big bike development had stalled in mid-decade.

Though revolutionary when introduced, the Z1 wasn’t perfect. The mild steel double cradle frame flexed under load, the 36mm forks were under-specified, and the rear suspension was over-sprung and under-damped. To lighten the steering, Kawasaki’s engineers gave the Z1 a sharp, 26-degree steering rake, but it came at a price; sudden direction changes would induce weaves, which, combined with the lack of trail, could quickly get out of hand. Neither was the single disc/drum brake combo up to hauling 530 pounds of motorcycle down from 125mph.

When the Suzuki GS750 arrived in 1977, Kawasaki countered with the triple disc-brake KZ1000. It looked cooler, and maybe stopped better, but the extra 100ccs produced little if any extra power, and the flexy frame remained. The liter-class still set the performance benchmark, but with the GPz1100 a couple of years away, Kawi’s Z-bike needed a makeover to extend its life.