MASTERPIECE‼️ How Honda's 5-Cylinder Tamed the 2-Stroke Beast of '60s Grand Prix

This story begins with a big dream in the mind of a man named Soichiro Honda. For him, just making motorcycles wasn't enough. He wanted to conquer the world, and the best way to do that was by proving his company's technological prowess on the racetrack. Winning on the circuit was everything, but he had one non-negotiable condition. Victory had to be achieved with a four-stroke engine. At a time when other manufacturers were starting to embrace the simpler, more powerful two-stroke engine, Soichiro Honda dismissed it as noisy and dirty. For him, the beauty of a complex four-stroke engine was the ultimate expression of engineering greatness. The turning point came in 1954. Soichiro Honda traveled to Europe and saw the legendary Isle of Man TT for the first time. There, he wasn't just amazed by the speed of the European bikes. He promised himself that one day, Honda would return to that island and win. To prove his seriousness, he even bought the reigning world champion bike at the time, a F.B. Mondial 125cc, not to copy it, but to take it apart and study every last bolt in his headquarters. Now, this is where the real challenge began. His stubborn principle of sticking with four-stroke engines put Honda at a disadvantage. A two-stroke is naturally more powerful, because it produces power on every engine revolution, while a four-stroke needs two revolutions for a single power stroke. To get around this, Honda's engineers had only one path forward, make their engines rev much higher than any engine ever had before. And to reach sky-high RPM, the internal components had to be incredibly light and move with lightning speed. This logic inevitably led them to an extreme design, adding more and more tiny cylinders. This long journey is what ultimately gave birth to a crazy masterpiece, the Honda RC149, a 125cc race bike with five cylinders. In January 1959, Honda's first race bike, codenamed the RC141, was completed. Unlike the single-cylinder Mondial engine they had studied, Honda immediately took an ambitious step by creating a DOHC twin-cylinder engine. Its design was slightly influenced by other European race bikes, like the NSU-Renmax, but Honda's engineers still gave it their own original touch. Unfortunately, its initial performance was underwhelming. The RC141 only produced about 18 brake horsepower, which wasn't enough to compete at the world level. In the summer of 1959, the Honda team finally arrived at the Isle of Man TT. Their arrival turned heads. The team looked incredibly professional, with mechanics in clean white uniforms working with immense discipline. The bike they brought wasn't the RC141, but its upgraded version, the RC142. The main difference was the use of a four-valve per-cylinder head, which was flown in directly from Japan after practice sessions showed the two-valve version lacked power. Technically, the RC142 used a 124.6 cubic centimeter DOHC twin-cylinder engine with a 44 by 41 millimeter bore and stroke. However, its backbone-style frame and leading link front suspension proved unsuitable for the bumpy road course. The race results were an important lesson. The winner, Tarquino Pravini of the MV Agusta team, was untouchable. However, the Honda bikes showed excellent reliability. Naomi Taniguchi finished in 6th place, followed by Jichi Suzuki in 7th, and Teisuke Tanaka in 8th. This performance earned Honda the team trophy in their debut, beating major manufacturers like MV Agusta, MZ, and Ducati. After the race, the team immediately disassembled the engines from the frames, packed them up, and shipped them back to Japan for analysis. This showed that their main goal was to gather data. Being defeated on speed gave them a clear picture of how far they had to go, while the team trophy proved that their four-stroke foundation was solid. Learning from the RC142's weaknesses, Honda made major improvements for the 1960 season with the RC143. The leading link front suspension was replaced with more conventional telescopic forks used in racing. Additionally, the engine was tilted forward 35 degrees to improve the center of gravity and cooling. As a result, engine power increased to about 22 to 23 horsepower at 14,000 revolutions per minute. Although it still couldn't match the of the MV Agusta and MZ bikes, the RC143's improved performance was a sign that Honda was a serious threat for the future. For the 1961 season, Honda perfected their bike with the release of the 2RC143. The most important change was to the chassis. The spine-type frame was replaced with an open double-loop frame inspired by Norton's legendary Featherbed chassis, which was famous for its great handling. This new design drastically improved the bike's stability. The engine was similar to the RC143, but with a few adjustments, its power now reached 23 horsepower at 14,000 revolutions per minute. The combination of a superior chassis and a reliable engine proved to be a winning formula. The 1961 season was a year of total domination for Honda, with the 2RC143 winning 8 out of 11 races. Honda's first victory was achieved by Australian rider Tom Phyllis at the Spanish GP. Subsequent wins were secured by other great riders like Luigi Taveri, Jim Redman, Kunimitsu Takahashi, and Mike Halewood. By the end of the season, Honda had won the Constructor's World Championship and the Rider's World Championship with Tom Phyllis. In just two years, Honda had reached the pinnacle of Grand Prix racing. Amid their success, Honda's research team tried a different development path, by creating the RC144. While previous bikes had succeeded with an over-square engine design for high RPMs, the RC144 was the opposite. This bike used a long-stroke engine with a 42x45mm bore and stroke. The goal was likely to find better mid-range torque. However, the results were disappointing. The RC144 only produced 22bhp at 13,000rpm and was used only once in an official race. This failure taught an important lesson. To beat two-stroke engines, the only way was to chase the highest possible RPM. Honda themselves called the RC144 an unfortunate bike. After the failure of the RC144, Honda returned to the right path with the RC145 for the 1962 season. This bike was a further development of the 2RC143. Its main innovation was a new camshaft drive system, which was changed from a bevel gear shaft to a gear train. This new system was stronger and more precise at high engine speeds. The engine's power increased slightly to 24hp at 14,000rpm. With this bike, Swiss rider Luigi Taveri won the 125cc world championship in 1962, continuing Honda's dominance. By the mid-1960s, the competition grew fiercer. Other Japanese manufacturers, Suzuki and Yamaha, began to pose a serious threat with their increasingly advanced two-stroke engines. Their two-strokes started producing more power than Honda's twin-cylinder four-stroke. Honda's engineers realized that the era of their twin-cylinder dominance was coming to an end. The competition on the track turned into a technological arms race among the Japanese manufacturers. In response, Honda took the next step, adding more cylinders. They developed the RC146, a 125cc bike with an inline-four engine. This bike was essentially a miniature version of their already successful 250cc four-cylinder engine. The 1964 version, known as the 2RC146, produced 28bhp at 16,500rpm, with a redline of 18,000rpm. To keep the engine in its narrow powerband, the bike was equipped with an 8-speed gearbox. The next version, in 1965, the 4RC146, could even produce 30bhp. However, the bike was known for being unreliable due to its complexity and often had issues with carburetion and ignition. Even with four-cylinders, the pressure from Suzuki and Yamaha didn't let up. Yamaha was even rumored to be developing a two-stroke V4. Faced with this, Honda decided to take an even more extreme step with the RC148 project, a 125cc bike with an inline-five engine. The concept was quite clever. The RC148 was essentially a development of their successful 50cc twin-cylinder engine, the RC115. The logic was to combine two and a half of those engines to create a single five-cylinder unit. Technically, the design was more like a six-cylinder engine, with one of the middle cylinders removed to address vibration issues. The RC148 debuted in the final race of the 1965 season at the Japanese GP. With 31.5hp, the bike immediately finished in second place and set the fastest lap, a very promising start. For the 1966 race season, Honda refined the RC148 prototype into the RC149. This was the pinnacle of Honda's extreme engineering philosophy, a bike with specs that sound incredible, even by today's standards. Its heart was an engineering masterpiece, a 124.42cc four-stroke DOHC inline-five engine with a total of 20 valves. To rev as high as possible, its pistons were made incredibly small, with a bore of 35.5mm and a stroke of just 25.14mm, often compared to the size of an espresso cup. As a result, this engine could pump out 34hp at an astonishingly high 20,500rpm, with a redline that could hit 21,500rpm and occasionally even touch 23,000rpm. Because its power was only available in a very narrow rev range, the bike had to be fitted with an 8 or 9-speed gearbox with very close ratios. All this technical wizardry was wrapped in a very light package. With a dry weight of only 187 pounds, thanks to the extensive use of exotic materials like magnesium. With all that, the RC149 could reach speeds of over 130mph. Building and maintaining the RC149 was incredibly complex. Honda's team mechanics often joked that their fingers felt too big when working on the tiny engine components. For some of the smallest parts, like the valve retainers, they had to use tweezers. Additionally, technical challenges like managing the vibrations of a 5-cylinder engine and ensuring all 5 carburetors worked in sync were major hurdles that Honda's engineers successfully overcame. Riding the RC149 was no easy task. The engine had almost no power at low revs, and would stall if the rpm dropped below 17,000. It took a highly skilled rider to control it, and that person was Luigi Taveri. The Swiss rider was known for being experienced, technically smart, and calm. The perfect combination for this bike. With his small stature, he was also a perfect fit for a lightweight class race bike. After a hugely successful 1966 season, where Honda won the constructor's title in all 5 racing classes, the company made a big decision. At the end of the 1967 season, Honda announced it would temporarily withdraw from Grand Prix racing to focus on its Formula One car program. At the same time, the sport's governing body, the FIM, grew concerned. The cost of developing race bikes had skyrocketed, and the complex machines made it impossible for smaller teams to compete. In 1967, the FIM announced drastic technical rule changes that would take effect in the 1969 season. These new rules were intentionally designed to limit engine complexity to cut costs. For the 125cc and 250cc classes, the number of cylinders was limited to a maximum of 2. For all classes, the number of gears was limited to a maximum of 6. With one rule change, all the advanced multi-cylinder bikes became illegal. The Honda RC149 with its 5 cylinders, the RC166 250cc with its 6 cylinders, and the 4-cylinder bikes from Suzuki and Yamaha could no longer be used. This led many major factory teams, including Honda, Suzuki, and Yamaha, to withdraw from the championship. The era of extreme technological warfare was over.