With an experienced team and a lot of data.
Protect your 1975 Suzuki RE5 from the unexpected.
It looked like rotary engines were the next big thing in the early 1970s. Mazda had embraced the technology and though rotor tip failures had practically bankrupted the company (and did bankrupt NSU), Mazda stayed the course. The RX2, RX3 and RX4 were blisteringly fast (if terribly thirsty) and Mazda hit a home run with the RX7 a few years later in 1979. Meanwhile, Chevrolet tested a rotary engine in the Corvette and AMC designed the 1975 Pacer specifically for a rotary, although the production version never got one.
The rotary seemed like a great fit for motorcycles, meanwhile, and Hercules, Van Veen and Suzuki produced bikes. Kawasaki’s X-99, Honda’s CRX and Yamaha’s RZ-201 were tested, displayed at motorcycle shows, then parked. Rotary bikes suffered the same problems as the cars. Rotor tips burned, exhausts ran extremely hot and the engines lacked torque.
The German Hercules company built 3,000 bikes, Dutch entrepreneur Van Veen sold 37 frighteningly expensive machines with Citroen rotary automobile engines, and Suzuki built 6,350 RE5s. It was a short-lived era in bike design, as it was all over by 1976. Suzuki sold one RE5 in Germany that whole year. For those looking for a rotary to add to a bike collection, the Suzuki RE5 is probably the best bet. Most were collected as oddities and their underwhelming performance means many of them don’t have many miles on the clock.
Like a lot of rotary designs, the RE5 looked promising on the drawing board. The huge radiator was distinctive, and the 497 cc single-rotor engine was compact and largely vibration-free, but plumbing was crammed into the frame and there was little torque below 5,000 rpm when the bike woke up and revved to 12,000 rpm. At 617 lbs it was porky, and 62 bhp just wasn’t really enough, especially when the gas mileage was worse than similar four-cylinder machines. Another strike against the Suzuki RE5 was its $2,495 price tag, which was seen as excessive for a bike with that kind of performance.
With few RE5s ridden far, it’s hard to know how reliable they are. The engines do have a fierce appetite for spark plugs, which are hard to find. Owners in period also complained about ineffective heat shields, hesitant throttle response and lack of engine braking. The side-mounted oil injection carburetor was also finicky.
The main issue with owning an RE5 is finding a skilled mechanic. Rotary engines are a different kettle of fish, and specialists are few and far between. The factory’s solution to engine problems when the bikes were new was to exchange a defective motor for a new one, but that of course is no longer possible. When shopping for an RE5, buy only the best low-mileage example available, and don’t be afraid to haggle with a proud owner as this is a thin market.