Like the ‘50s jet age and space age of the ‘60s, “rotary power” was a hot topic across the 1970s automotive sphere. Billed by apostles as the next phase in internal combustion, it was, for a time, just that. The principle was deceptively simple. It features a three-sided rotor (almost triangular in shape) spinning around a crankshaft inside an oval-esque combustion chamber, which provides three power cycles for every revolution of the rotor. Confused yet? Many smart people were despite the fact that a basic rotary engine has just two moving parts. Check out this link for a good animation.
The rotary passion began for Mazda when it licensed German inventor Dr. Felix Wankel’s technology from NSU in the early 1960s. Mazda set about the long process of trying to perfect an engine for mass production. By all accounts, it succeeded. Over more than four decades Mazda sold eight different model names, from the original Cosmo Sport up through the latest RX-8, in layouts as diverse as sports cars, coupes, wagons, sedans and even a pickup.
Just as few automakers followed Mazda’s lead in building rotary-engine cars, in the motorcycle realm, among equally few players, Suzuki did best. Its RE-5 was a flagship model that lasted only two years 1975 and ’76. Coincidentally, Mazda launched its RX-4, the highest iteration of company’s rotary 2+2 coupe, in 1974. So for two short years, customers could buy both a new Mazda rotary-powered car and a new Suzuki rotary-powered bike. Wonder if anyone actually did. If that was you, please write us!
“Piston engine goes ‘Boing, boing, boing’…but the Mazda goes ‘Hmmmm.’” This period commercial for the Mazda rotary is not as famous as Volkswagen’s 1959 “Think Small” campaign, but it captures the car’s essence just as beautifully. Which is to say, Mazda’s line of rotary cars and trucks, which ran from 1967 to 2012, delivered smooth, lightweight and technically sophisticated performance.
The RX-4 was an attractive Japanese sporty coupe, reminiscent of the first Toyota Celica liftback of the early-‘70s. Although its front-end styling was unremarkable, setting the car off was its tapered rear roofline—think early Datsun 240Z—and its blackout Kamm tail with quad taillights. A neatly styled interior featured well-tailored bucket seats, wraparound instrumentation and a full center console – prescient because now, over 40 years later, this same layout still rules. Its suspension was typical for the day, including MacPherson struts in front and a live rear axle, plus front disc and rear drum brakes.
Naturally though, what made the RX-4 wasn’t the styling but its two-rotor “13B” engine displacing 1,308-cc and producing 125 hp. Weighing 2,620 pounds, the RX-4’s power-to-weight ratio registered at roughly one horsepower per 21 pounds – spritely but hardly earthshaking. And like other rotary engines, the RX-4’s Achilles heel was the rotors’ “apex seal” wear and fuel consumption. That said, when properly hopped up, rotary engines will go like gangbusters. Indeed, Mazda won the 1991 24 Hours of Le Mans with a rotary, and amazingly remains the only Japanese company to have conquered the French classic.
If packaging a rotary engine under a car’s hood—where the plethora of hoses, lines and fittings can be easily hidden—is challenging, imagine miniaturizing and sanitizing it for a motorcycle. Among the Asian bike makers that studied rotaries, only Suzuki was brave enough to enter production with one. The RE-5 used a traditional steel frame, suspension, spoke wheels and a combination of dual front disc and rear drum brakes. But from there on, it was all ahead Flash Gordon. Futuristically styled by Giorgetto Giugiaro, the RE-5 had distinctive angular bodywork, possibly the most polishing and chrome ever fitted to a Suzuki, and a wild instrument pod with a translucent cover that rotated (mimicking the rotary engine) forward to reveal the gauges. That the RE-5 remains as wild today, both in engineering and styling, as in 1975 is a testimony to just how ambitious the program really was.
Performance-wise, the RE-5 was positioned more as a premium standard or tourer than a sportbike. Like the Mazda, the single-rotor, 497-cc engine makes a characteristic hum that belongs exclusively to rotaries. The powerband is reasonably broad and energetic, but performance is not memorable compared to the era’s big multi-cylinder superbikes. Rated at 62 hp and weighing 573 pounds wet, the RE-5 delivered a power-to-weight ratio of one hp for a bit over nine pounds. Even when the rider’s weight is considered, it’s still better than the Mazda RX-4.
Unorthodox, at times temperamental, and hard to fathom even for enthusiasts, the rotary engine lasted for only two years for Suzuki, but ranged over some 46 remarkable years for Mazda, beginning in 1967 and ending in 2012. Although the RX-4 and RE-5 were noteworthy and aspirational side notes to the automotive and motorcycle worlds, in today’s collector climate they have not appreciated dramatically. The Suzuki rotary commands up to about $6,800 but the Mazda RX-4 attracts only about $7,500 today, based on available sales data. These figures do offer one positive, though: If you or parents didn’t get to own this wondrous pair in 1975, the opportunity still exists today.
Just remember to go, “Hmmmm.”