The Birth of Honda’s General-Purpose Engine

In post-World War II Japan, Honda yearned to make people’s lives easier, and create tools that would be useful in everyday life. This desire eventually led to the development of an auxiliary engine for bicycles, which led to the Super Cub, and ultimately to the birth of Honda Power Products.

“Sachi, see what I made. Try it out.”

In 1946, Honda founder Soichiro Honda brought home a bicycle with an auxiliary engine attached. Sachi was Soichiro’s wife. Concerned that she would be riding the bicycle on a busy street, Sachi wore her “best” Monpe trousers (traditional Japanese work pants), and was seen riding the bicycle with the auciliary engine.

“He claims to have made it because he felt sorry for me having to ride a bicycle to buy groceries, and maybe that was a little a part of it. I honestly think, though, that he just wanted to see if a woman could handle it.” (Sachi)

After riding the bicycle for a while, Sachi said,

“My best monpe is covered in oil. This won't do. Customers will be angry with this.” (Sachi: *01 “Lessons to Hand Down” 50 Years of Challenges)

The reason her Monpe was dirty was the backflow of mixed fuel from the carburetor. Since then, Honda improved the bicycle auxiliary engine (commonly known as in Japan as “Batabata”), and began sales in October as the first product of Honda Technical Research Institute established in September 1946.

The Honda bicycle auxiliary engine later evolved into the A-Type engine, which launched in November 1947. This was further evolved into the Cub F-Type, which could be mounted on the rear wheel to keep the rider’s clothing comparatively cleaner, and was released in 1952.

In 1953, Kyoritsu Nogyo (now Yamabiko Corporation), an agricultural machinery manufacturer, learned of Honda’s highly reputed A-Type and Cub F-Type engines, and requested the development of a small engine for a backpack spreader. On September 24, 1948, Honda established a new company, Honda Motor Co., Ltd. At the time, Honda’s president, Soichiro Honda, had witnessed the harsh working conditions of people in rural and fishing villages across the country, and was driven by the desire to create tools that could alleviate their labor using Honda’s engine technology and help lift Japan out of poverty. The development of this general-purpose engine provided the perfect opportunity to realize this vision. This was the beginning of what is now known as Honda Power Products.

Backpack spreaders became agricultural machines in high demand during the post-war period as Japan sought to mechanize its agriculture, alongside tillers and threshing machines. Honda began development using the basic layout of the Cub F-Type’s two-stroke engine launched the previous year in 1952. The resulting H-Type engine, launched in October 1953, gained a positive reception for its compact size, lightweight design, and ease of use, reaching monthly production of over 5,000 units within six months of its release. This was Honda’s first foray into engine supply to other companies; the beginning of Original Equipment Manufacturer (OEM) production.

The H-Type engine was not limited to use in sprayers for orchards and fields but also powered spreaders and water pumps, and even found widespread use in coffee plantations as far away as Brazil.

H-Type engine users praised the engine, while also providing feedback for improvements. In response, Honda began developing a lightweight, dirt-resistant, high-output 4-stroke general-purpose engine in August 1954. Four months later, in December 1954, Honda unveiled the 4-stroke T-Type engine with output increased from the H-Type’s 1 horsepower to 2.5 horsepower. This compact engine achieved exceptional fuel efficiency, consuming only approximately 0.54 liters of gasoline per hour of continuous operation. Despite its high output, the T-Type continued to operate even when used in various angles, such as backpack or shoulder-mounted configurations. Compared to two-stroke engines, the T-Type featured quieter operation, reduced vibration, and lack of burned engine oil, making it a user-friendly general-purpose engine.

Honda’s History (※02) published in 1955 stated, “When the T-Type engine was introduced in December 1954, its outstanding performance, including gasoline consumption of just three cups per hour of continuous operation, 2.5 HP output, complete waterproofing, manual rope-starting, no vibration, and no stalling even when tilted at any angle, made it a coveted item for farmers.”

Following the development and sale of the T-Type engine, Honda’s general-purpose engines expanded beyond their original applications, spraying and spreading, to be used in various fields such as power cultivators (agricultural machinery for weeding and soil cultivation), tillers, construction machinery, and generators.

As a result, Honda followed up the T-Type with the introduction of the four-stroke V-Type engine in 1956, increasing output to 4 horsepower. In 1958, Honda launched the improved VNC-Type and VND-Type engines, further increasing maximum output to 5 PS.

The further evolved VNC-Type and VND-Type engines were compact and lightweight, yet featured automatic centrifugal clutches and recoil starters for improved starting performance, and adopted aluminum fan covers to enhance quietness.

Honda’s power products business, which began in 1953 shortly after the end of World War II with the development of a general-purpose engine commissioned by an agricultural machinery manufacturer, expanded beyond the agricultural sector to supply general-purpose engines to manufacturers in a wide range of industries, including construction. Honda continued to play a significant role in various fields worldwide, with general-purpose engines at the core of its operations.

References
*1 Honda Motor Co., Ltd. (1999) “Lessons to Hand Down” 50 Years of Challenges (Japanese language only)
*2 Honda Motor Co., Ltd. (1999) Honda Motor Co., Ltd. History (7-Year History Reprint) (Japanese language only)

Honda General-Purpose Engines Take on the World

Since first appearing in 1953, Honda’s general-purpose engines spread throughout the world, not only for spraying and spreading, but also for use in agricultural and industrial machinery. The desire to help people in need and to assist with laborious work using Honda engines led to the development and sale of Honda tillers and the next generation of general-purpose engines.

Engines to mechanize the work of a million people

Honda’s general-purpose engines evolved steadily from the H-Type in 1953 to the T-Type and then the VN-Type. Lightweight, compact, and easy to handle, these engines offered improved durability, reliability, and power, making them accessible to a wide range of users and capable of assisting with various tasks.

Output quadrupled from 1 to 4 horsepower, expanding its applications. By mechanizing tasks previously performed by people or tools in agricultural work and construction sites, Honda’s steadfast belief, as expressed by its founder, Soichiro Honda, that its engine technology could help lift Japan out of poverty, began to bear fruit.

By the 1960s, Honda not only supplied general-purpose engines to other manufacturers but also launched a series of self-developed products such as tillers, outboard motors, and generators powered by general-purpose engines. These products, which embodied Soichiro’s vision, contributed to the mechanization of many tasks.

During this time, Honda began developing a new general-purpose engine that could compete on the global stage. This engine was known internally as the ME (Million-selling Engine) concept. In other words, it was designed to mechanize the work of one million people.

The Million Engine was designed to be lightweight, compact, quiet, and fuel-efficient, just like the H-Type, T-Type, and VN-Type engines. Development began with the belief that selling one million units would make the work of one million people easier.

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In developing the G-Type engine, Honda prioritized reliability, durability, and longevity, and began sales of the G150 and G200 in 1977. Four-stroke engines can seize up and break down when engine oil levels drop too low. To address this, the G150 and G200 were equipped with an oil alert mechanism that automatically stopped the engine before oil levels dropped below the specified minimum.

This mechanism, now standard in many engines, prevents major issues by stopping the engine and alerting the user to the need to replenish engine oil before problems occur.

The G150 and G200 engines created a phenomenon in Southeast Asia where they were “red and white engines that sell well without being shown on the storefront.” In Thailand and Indonesia, the number of users who connected the G150 and G200 engines to propellers via long shafts to create longtail boats had surged, contributing to the mechanization of fishing and small vessel transportation.

At the same time, Honda strengthened its OEM sales to agricultural and industrial machinery manufacturers, achieving annual sales of 300,000 units in the first year of release in 1977. By 1982, it reached the ME initiative’s annual target of one million units sold, becoming a global hit product, especially in Southeast Asia.

Honda developed the G-Type engine primarily targeting business use, but to further mechanize the work of even more people, it recognized the need to expand the market with a versatile engine suitable for a wider range of applications accessible to the public. This led to the development of a new engine.

This led to the development of the GX-type engine, which is now the mainstay of Honda’s general-purpose engines. During the development phase, Honda began development with the slogan “ZE” (Zillion, or an unimaginable number), far surpassing the ME Concept.

The concept was to create an engine that was lighter and more compact than the G-Type engine, while also achieving more output, better fuel efficiency, and superior quietness and durability. At the same time, the oil crisis of the 1970s, including the 1979 energy crisis, shifted the focus toward energy conservation, and there was a strong demand for improved fuel efficiency. To achieve this, Honda decided to develop an overhead valve (OHV) engine, which is more fuel efficient, rather than the side valve (SV) engine used in the G-Type engine.

The biggest challenge in developing this engine was to ensure compatibility with the mount dimensions specified by OEM manufacturers, which were based on the SV G-Type engine. The goal was to maximize mount compatibility while adhering to existing specifications.

In 1983, sales of the GX110 and GX140 began. Initially, there were doubts about introducing a new engine alongside the already popular G-Type, but as its economic efficiency, lightweight design, and ease of use became recognized, the GX engine established itself as the de facto of general-purpose engines. In fact, many engine manufacturers, starting with China, adopted its OHV mechanism, tilted cylinder, and low center of gravity, leading to the widespread availability of GX-like engines.

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Furthermore, by actively conducting engine matching activities (application engineering) to adjust engine components to meet the specifications of various OEM manufacturers’ products, the GX engine fulfilled its destiny as the “ZE” engine upon its release, and grew into a foundational product supporting Honda’s Power Products business.

Mechanizing even more tasks

Honda did not supply general-purpose engines to OEM manufacturers who sold products that competed with Honda’s own, such as tillers, generators, and lawn mowers. However, based on the belief that removing this barrier would allow more people to be freed from laborious tasks through mechanization, Honda shifted its strategy and began OEM sales to competing manufacturers. This resulted in a significant increase in sales, enabling more people to mechanize their work.

In 1997, Honda began sales of the GX22 and GX31 engines. These engines, internally referred to as the M4 (Mini 4-Stroke), were developed as small-displacement 4-stroke engines for handheld power tools such as brush cutters.

At the time, most products in the handheld market were powered by lightweight, easy-to-handle 2-stroke engines. However, 2-stroke engines burn lubricating oil along with fuel, not only resulting in exhaust gases containing burnt oil, but loud, high-pitched engine noise, poor starting performance, and the inconvenience of preparing a mixture of gasoline and engine oil.

In contrast, 4-stroke engines offered superior quietness and cleaner exhaust emissions. Handheld products, however, often require operators to move the machine at various angles while working, making it difficult to maintain a consistent lubrication path for the engine oil. Additionally, 4-stroke engines, which have more parts and are heavier than 2-stroke engines, were considered unsuitable for handheld products.

To overcome these issues, Honda developed a rotary slinger pumping lubrication system unaffected by engine tilt. By adopting this mechanism in the GX22, Honda achieved stable engine operation at any angle, giving birth to the world’s first lightweight 4-stroke engine capable of 360-degree operation.

The GX25 which followed further achieved a more compact and lightweight design by adopting an oil-immersed timing belt OHC structure. This technology has been adopted not only in Honda’s handheld products but also by many OEM manufacturers, contributing to comfortable working environments.

Honda’s passion, that began in 1953 with the development of a general-purpose engine to mechanize work and make people’s lives easier, has been inherited by the GX-series engines.

World Standard Model and the Future of Honda Power Units

Honda’s Power Products business began in 1953, with the launch of the H-Type general-purpose engine. At its core was founder Soichiro Honda’s passion to contribute to society through technology. Now, more than 70 years later, Honda’s Power Products business is focused on the next generation.

In 1983, the GX engine was launched with the goal of achieving the ZE (“Zillion Engine,” with an unimaginably large number of sales). On release, this engine earned praise throughout the world, and grew into a core product supporting Honda’s Power Products business.

The GX engine was particularly praised for its high durability, lightweight compact size making it easy for anyone to handle, its fuel efficiency offering great economy, and significantly reducing the maintenance burden on users. The defining feature of the GX engine was its shift from the SV (side valve) structure of the preceding G-series engines to an OHV (overhead valve) design. This new configuration delivered higher output, better fuel efficiency, and quieter operation. It also needed fewer parts than the SV engine, reducing manufacturing and sales costs.

Furthermore, the GX engine incorporated numerous new mechanisms enhancing its performance. These included mechanical decompression for easier starting and a maintenance-friendly, point-less transistorized magneto ignition system. For installation compatibility, the engine was successfully downsized by approximately 30% compared to the initial development target, enabling seamless integration into existing products originally equipped with conventional engines, fulfilling a key development objective. These technological challenges led to the GX series engines earning such high acclaim that they became known as the “industry standard” for general-purpose engines.

Sales of the GX engine grew immediately after release, coming within striking distance of the annual target of 3 million units. It gained high acclaim not only in the largest markets, North America and Europe, but also in Southeast Asia.

However, the downside was that the GX engine’s core design concept—the OHV mechanism with inclined cylinder—was adopted by general-purpose engine manufacturers worldwide. This forced Honda into a new competitive landscape. Consequently, Honda pursued continuous product improvements to enhance performance while also implementing cost reductions, enabling expansion into emerging markets in Southeast Asia and Africa.

Honda’s approach to emerging markets involved deploying service caravans in rural and fishing villages. This introduced the concept of after-sales service—regular repairs and adjustments—to these regions.

This approach, adjusting poorly performing products and repairing those with issues, could not be matched by competitors focused solely on low prices. Emerging low-cost manufacturers rapidly growing at the time priced their products so low that customers could simply buy a new unit if problems arose, and even included replacements for easily breakable parts in the package.

Consequently, Honda’s reputation for high durability, rapid parts supply, and robust service systems elevated its brand value. This after-sales service philosophy was a continuation of the approach Honda had followed since its founding for both motorcycles and automobiles.

The reputation of the GX series engines also influenced Honda’s OEM sales of general-purpose engines to other manufacturers. While OEM sales typically avoid supplying products to competitors, Honda supplies its general-purpose engines even to manufacturers that compete with its products. Honda sells various products like lawn mowers, snow blowers, water pumps, and tillers, yet it also supplies general-purpose engines to manufacturers that produce and sell similar products.

This approach reflects the philosophy of Honda’s Power Products business. Honda believes that while selling finished power products brings happiness only to those customers, OEM sales increase the number of products powered by Honda’s general-purpose engines. This, in turn, creates greater potential to bring happiness to more people. This philosophy can be directly attributed to Soichiro Honda’s passion to “help people and society through technology.”

Furthermore, Honda’s general-purpose engines are adopted by various construction machinery manufacturers as power sources for equipment used in the construction industry. As a result, Honda’s OEM sales volume globally accounts for just under 70% of its Power Products business. Honda’s current OEM supply network now spans over 50 countries and exceeds 2,000 companies worldwide.

Honda’s general-purpose engines are now entering a new era. This involves adapting to new demands, such as environmental performance and carbon neutrality.

In 2005, Honda introduced the iGX engine, featuring the world’s first*1 newly developed electronic governor system (engine speed electronic control technology) Honda’s newly developed battery-free electronic speed control technology to constantly monitor engine speed and throttle position to maintain constant engine output. For example, even when grass becomes entangled in the rotating blade during use, increasing engine load and causing RPM to drop, this technology maintains the set engine speed.
*1 Honda internal research as of 2005: World-first as a single-cylinder general-purpose engine

This iGX engine achieved emissions reductions exceeding the world’s strictest EPA (U.S. Environmental Protection Agency) and CARB (California Air Resources Board) regulations by approximately 30%. It met stringent emissions standards not only in the U.S. but also in Canada, the EU, Australia, China, and elsewhere, achieving world-leading environmental performance. Furthermore, compared to competing manufacturers’ products, it improved fuel efficiency by approximately 15% per hour* and reduced noise by approximately 4 dB.
* Fuel efficiency based on EPA mode operation; noise based on EU noise regulations/generator measurement mode.

Regarding carbon neutrality, Honda has produced and launched the eGX, a power unit that combines a battery and motor. By cooling the basic structure of the battery and motor, which houses precision electronic components, to a level higher than that of an engine, and designing the unit to withstand dust and vibration, conditions engine-powered units could not operate under, Honda achieved zero emissions, taking the first step toward preparing for the carbon-neutral era.

eGX began OEM sales to finished machine manufacturers in June 2021, and launched leasing in 2022. In March 2022, Komatsu announced its electric compact excavator PC01E-1 powered by eGX. As various implementations progress, Honda expects to help solve issues like noise and exhaust emissions in residential area construction and nighttime work.

It is, of course, unlikely that small construction machinery and agricultural equipment, which have lower environmental impact compared to automobiles and motorcycles, will immediately face stringent emissions regulations. However, Honda is preparing for that time to come.

More than 70 years have passed since Honda developed its first universal H-Type engine for agricultural sprayers in 1953, just five years after the company’s founding. Today, Honda’s general-purpose engines power not only Honda’s own products but also a wide range of work machines worldwide, serving as the driving force for agricultural machinery, construction equipment, and more. As the times change, power sources are expected to evolve from engines to electric and other power units. However, Honda’s belief, of helping people and society through technology, will continue to support people’s lives.

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