Honda revolutionized motorcycling as we know it with the introduction of the the Universal Japanese Motorcycle, or “UJM” for short. The premise is simple–consumers should be able to buy one motorcycle that can do everything, and it should do everything well. A UJM needs to be nimble enough to navigate city centers in traffic, but large enough to be viable highway transportation. A UJM should have a suitably sporty suspension, but be compliant enough to allow for an entire day of riding. A UJM has to be an easy-to-ride first motorcycle, but leave enough of a challenge to encourage rider improvement. And on top of all that, a UJM must be cheap to run and easy to take care of. In 1969, Honda released the ubiquitous CB750 inline-four cylinder, air-cooled, Universal Japanese Motorcycle as a vehicle that they could sell in virtually any market on the planet. And sell it did, to the tune of over 500,000 units in the original 9-year production run.
By the mid-1970s, while CB750 sales were still relatively strong, Honda motorcycles had begun to grow stale. There was no real development since the CB750. The only “new” models from Honda were more CBs with less displacement, or special editions of the 750. Other Japanese manufacturers quickly caught on to the UJM phenomena, introducing their own variations on the theme. Arguably, Kawasaki’s KZ offerings were even better than the Hondas that birthed the movement in the first place. Soichiro Honda built the foundations of his company on innovation, but the last real gamechanger was already several years old by 1976. This split Honda’s motorcycle development team into two camps–those who believed innovation would come through perfection of Honda’s current line of the Universal Japanese Motorcycle, and those who, looking ahead to the coming decade, concluded that Honda needed to be on the cutting edge of motorcycle technology to fulfill Honda’s vision.
That first group understood that there was still much improvement to be had with the inline air-cooled architecture they had spent so long developing. This movement was led by engineer Shoichiro Irimajiri, who certainly knew what he was doing. A decade earlier, Irimajiri fought off the influx of dominant two-stroke Japanese MotoGP entries with the development of the legendary Honda RC166, a 250cc inline six air-cooled four-stroke race bike that swept all 10 races it was entered in, and deserves its own article altogether. Irimajiri stuck to what he knew best, and led the charge for the Honda CBX, a 1000cc air-cooled inline six motorcycle based on the beloved CB750. If an inline six motorcycle sounds insane, well, it was. Making its debut in 1978, the CBX produced triple-digit horsepower–impressive today, virtually unheard of in the late ’70s, especially in a street bike. While the 24-valve motor was a marvel of engineering, the chassis itself was, well, the same general architecture that was growing stale in the CB750. Basic telescoping front forks, CB750-based tubular frame, and twin rear shocks. While the CBX was only 2 inches wider than the CB750, it was over 100lbs heavier. The CBX, in its quest to perfect the air-cooled UJM, found itself further from the mark–too much bike for most riders, more difficult to maintain and costly to run than its predecessors, and most importantly, too expensive to begin with. The extremes that birthed the CBX would just as quickly lead to its demise by the 1982 model year, and by that time sales were so poor that Honda was donating remaining CBX stock to technical schools.
However, on the other side of the coin, that second group was taking risks. Big risks. While the CBX represented the logical conclusion of the Honda CB series, the latter group of engineers was making moves to redefine Honda’s identity for decades to come. Forget air-cooling, inline cylinder arrangements, and outdated chassis designs–these engineers were looking to pack as much technology into a motorcycle as possible. Learning from the shortcomings of the CBX, in 1982 Honda debuted a line of water-cooled, DOHC (That’s 4 cams per engine!) V-4 motorcycles that were a complete departure from anything they had attempted previously. Abandoning the idea of the Universal Japanese Motorcycle, instead 3 models were produced to fill different roles. The VF750S Sabre, a standard naked motorcycle most nearly resembling the UJMs of old, the VF750C Magna, taking advantage of the popularity of more laid-back cruisers, and (by 1985) the VF750S Interceptor fully-faired supersport, which would become legendary for decades in its own right. All sharing the same 750cc (with 500cc and 1100cc models available shortly thereafter) liquid-cooled V-4 engines, they possessed the performance of a inline 4 cylinder with the compact footprint of a V-twin. While the Magnas retained a large number of old-hat features–analog gauges and twin rear shocks (but oddly enough an electric fuel pump)–the Sabres and Interceptors were touted as the Motorcycles of the Future. Featuring a modern mono-shock rear suspension design and Honda’s new anti-dive TRAC system on the front forks, the chassis was just as advanced as the new motor. Beginning in 1983, Sabres even featured digital LCD displays for fuel level, water temperature, clock, and trip odometer. While the Magna, Sabre, or Interceptor could not individually replicate the sales success of the CB750, as a trio they did their best impression. As both a sales success and the pinnacle of motorcycle development of their time, the V-4 triplets set Honda back on the path of cutting-edge innovation.
That being said, Honda air-cooled inline motors didn’t just die overnight; derivatives of the CB750 would continue through 2003, albeit in basic, low-cost models. They would never again see the success of the original CB750, nor could they live up to the status of the later Honda V-4 bikes at the top of the motorcycle food chain. Further development of the V-4 after 1982 would leave us with legendary MotoGP bikes, supersports, sport tourers, and even adventure bikes based on the ideas established in 1982, the development of which really deserves its own series of articles. While the original CB750 introduced a generation to motorcycling, the liquid-cooled V-4 would allow Honda to chase perfection of motorcycling in ways the CBX never could.
Keep an eye out for an upcoming article series on the development and features of the Honda V-4 engine architecture from 1982-present, only on Burnt Clutches.
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