Honda S90 & ST90: Power, Pedigree & Practicality

In the illustrious history of Honda motorcycles, certain models stand out not just for their performance, but for their enduring charm, reliability, and sheer practicality. Among these, the 90cc machines, particularly the Honda S90 Super 90 and the Honda ST90 Sport Trail, hold a special place in the hearts of enthusiasts and collectors alike. These bikes, while sharing a common displacement, carved out distinct niches, offering riders everything from economical urban commuting to adventurous off-road exploration. Their simplicity, coupled with Honda's renowned engineering, ensured their longevity and continued relevance decades after their initial production.

The Enduring Appeal of the Honda S90 Super 90

The Honda S90, also affectionately known as the Super 90, represents a pivotal moment in Honda's expansion into the global motorcycle market. Introduced in the mid-1960s, this lightweight marvel was designed to be the next logical step for riders progressing from smaller machines like the Z50 or CT70. Despite its relatively modest engine size, the S90 delivered a surprising punch, earning its 'Super' moniker through its impressive performance figures for its class.

Horsepower, Performance and Practicality

At the heart of the Honda S90 was a single-cylinder, overhead-cam, 90cc four-stroke engine. This compact powerhouse was capable of pumping out approximately 8 horsepower, a figure that allowed the S90 to achieve a top speed of up to 65 miles per hour, especially when piloted by a lighter rider. More than just speed, the S90 was also incredibly economical, boasting fuel efficiency figures of 90 miles per gallon. This made it an ideal commuter bike, particularly for urban and suburban environments where high-speed motorway travel wasn't a necessity. Its light and agile feel, reminiscent of its smaller siblings, contributed significantly to its popularity as a versatile and economical mode of transport.

Interestingly, the S90's power output occasionally led to amusing situations. In 1960s Nevada, for example, specific regulations limited motorcycles for 14-16 year olds to no more than 6.5 horsepower. Despite the S90's actual output, Honda, with a touch of clever marketing, reportedly denied its engine produced more than 6.5 hp at the rear wheel in a letter to a dealership, a move to counter complaints from the Nevada Highway Patrol that the bikes were 'too quick'. This anecdote perfectly illustrates the S90's spirited performance relative to its perceived size.

Production Years and Legacy

The Honda S90 Super 90 was produced between 1964 and 1969. During this period, it solidified its reputation as a reliable, economical, and stylish motorcycle. Its design philosophy, which prioritised a small and light feel while offering enhanced performance over earlier models, resonated deeply with riders. It quickly became a popular choice, often serving as a highly desired second motorcycle for many households in the middle to late sixties.

The Distinctive Honda Benly 90

Closely related to the S90, and often confused with it due to their similar displacement and general aesthetic, is the Honda Benly 90. While sharing much of the S90's DNA, the Benly often featured a unique characteristic that set it apart: a rotary transmission. This innovative, albeit sometimes perplexing, gearbox design provided a distinctly different riding experience.

Understanding the Rotary Transmission

For those unfamiliar, a rotary transmission deviates from the conventional sequential gearbox. Instead of stopping at top gear, a rotary system allows you to upshift beyond the highest gear to find neutral, and from there, you can access either first or fourth gear. The design's intention was to simplify coming to a stop, theoretically sparing the rider the effort of downshifting through every gear. However, for many riders, this system felt counter-intuitive and, some might argue, 'asking for trouble' due to the potential for accidental shifts into neutral or first when expecting a higher gear. It certainly adds a layer of character to the Benly 90 that the S90 does not share.

Cosmetic Nuances and Collectibility

Beyond the transmission, subtle cosmetic differences and common wear points distinguish Benly 90 examples. While slight chrome pitting might be common on older models, other missing components, such as the chain cover, can be noted. However, finding a Benly 90 with its original front fender intact is often a bonus, as many were removed by riders. Furthermore, details like the rear footpegs, which notably do not fold on earlier Benly models (a manufacturing decision that contrasts with the folding pegs found on the S90), add to the unique characteristics that collectors look for. The presence of low handlebars, which for earlier models were actually OEM rather than aftermarket cafe bars, further highlights the specificities that differentiate these classic machines.

The Rugged Honda ST90 Sport Trail

Shifting focus from the road-oriented S90/Benly, we encounter the Honda ST90 Sport Trail. Released in 1973, the ST90 was a departure, designed with a distinct off-road bias. It was conceived as a more rugged, trail-focused version of the hugely popular CT90, which itself was based on the ubiquitous Super Cub. While the CT90 achieved remarkable success as a dual-sport machine, the ST90 aimed for a more specialised niche, targeting aspiring motocross enthusiasts and casual trail riders.

Design and Purpose

The 'ST' in ST90 stands for 'Sport Trail', aptly describing its intended use. It sat as a mid-way point between smaller minibikes (often called 'monkey bikes') and full-sized enduro motorcycles, making it accessible to a wide audience, from 10-14 year olds dreaming of motocross careers to adults seeking a lightweight, easy-to-manage trail bike. Unlike the CT90, the ST90 featured specific enhancements for off-road durability, including engine protection cradles, increased ground clearance, and higher front and rear fenders to better shed mud and debris.

The ST90 shared the CT series' fundamental architecture, notably a stamped steel backbone frame and an under-slung air-cooled engine. Its upright riding position and dual-sport credentials made it a versatile machine, though its primary focus was undoubtedly off-road adventures. Many adults found themselves drawn to the ST90 due to its remarkably low weight and the user-friendly nature of its automatic clutch and gearboxes, which significantly lowered the barrier to entry for trail riding.

Engine and Transmission Specifications

Powering the ST90 was a single-cylinder, air-cooled 89cc engine, featuring a single overhead cam (SOHC) operating two valves. This reliable powerplant was mated to a three-speed semi-automatic transmission, which transmitted power to the rear wheel via a centrifugal clutch and a chain final drive. This semi-automatic setup meant riders didn't need to manually operate a clutch lever, simplifying the riding experience, especially on trails where precise clutch control can be challenging for less experienced riders.

Suspension on the ST90 consisted of traditional hydraulic forks at the front and dual shock absorbers at the rear, providing adequate damping for varied terrain. It was also fitted with 'knobby' tyres both front and back, specifically optimised for off-road grip. Additional features such as twin engine protection bars, a rear luggage rack, and high handlebars further underscored its utilitarian and off-road-ready design.

Production and Collectibility

The Honda ST90 had a relatively short production run, from 1973 to 1975. Interest in the model wasn't as strong as Honda had anticipated, leading to its discontinuation after just two years. This short run, however, has made the ST90 significantly rarer than its CT90 sibling, and as a result, it has become quite collectible. Those who own them often extol their virtues, appreciating their simplicity, reliability, and capability as an inexpensive, entry-level trail bike.

Comparative Analysis: S90 vs. ST90 vs. CT90

To fully appreciate the distinct roles these 90cc Hondas played, it's helpful to compare their key characteristics. While all share the 90cc engine displacement, their design philosophies and target markets led to significant differences in their features and performance profiles.

Why These 90cc Hondas Still Matter

The enduring appeal of the Honda S90, Benly 90, and ST90 extends far beyond their original production years. They represent a golden era of motorcycling, characterised by simplicity, accessibility, and a focus on practical, reliable transport. Today, these machines are highly sought after by collectors and enthusiasts for several reasons:

• Nostalgia and Heritage: For many, these bikes evoke a sense of nostalgia for a bygone era of motorcycling. They are a tangible link to Honda's foundational years and its philosophy of making motorcycling accessible to the masses.
• Reliability and Simplicity: Built with Honda's legendary reliability, these bikes are relatively simple to maintain and repair. Their straightforward mechanical design means that many common issues can be addressed by a keen amateur mechanic, and parts, while sometimes challenging to source, are often available or can be fabricated.
• Economical Ownership: Even today, their high fuel efficiency makes them incredibly economical to run. This, combined with low insurance costs and minimal maintenance requirements, makes them an attractive option for those seeking a classic ride without exorbitant running costs.
• Collectibility: Particularly for models like the ST90 with its short production run, these bikes are becoming increasingly collectible. Well-preserved examples or those that have undergone sympathetic restorations command good prices in the classic bike market.
• Sheer Riding Fun: Despite their modest power, these bikes offer a pure, unadulterated riding experience. Their light weight and nimble handling make them a joy to ride, whether navigating city streets or exploring gentle trails.

Maintenance and Ownership Tips for Classic 90cc Hondas

Owning a classic Honda 90cc bike like the S90 or ST90 can be a rewarding experience. To ensure your vintage machine continues to run reliably, consider these general maintenance tips:

• Regular Oil Changes: Essential for any four-stroke engine, especially older ones. Use the recommended oil type and adhere to frequent change intervals.
• Tyre Condition: Check tyre pressure regularly and inspect for cracks or excessive wear. For ST90s, ensure the knobby tyres are still suitable for off-road use.
• Chain Maintenance: Keep the drive chain clean, lubricated, and correctly tensioned to prevent premature wear.
• Carburettor Care: Given their age, carburettor issues (such as blockages from old fuel) are common. Regular cleaning and proper fuel storage (e.g., using fuel stabiliser) are crucial.
• Electrical System: Inspect wiring for brittleness or damage. Ensure the battery is in good condition, especially for bikes that have been in long-term storage.
• Brakes: Check brake shoes and cables for wear and proper adjustment. Ensure braking is effective and smooth.
• Rust Prevention: Pay attention to chrome pitting and rust on the frame and exhaust. Regular cleaning and waxing can help preserve the bike's finish.
• Originality vs. Customisation: Decide on your ownership goal. While customisation can be fun, maintaining originality often enhances long-term value.

Frequently Asked Questions (FAQs)

Here are some common questions about the Honda S90 and ST90:

How much horsepower does a Honda S90 have?

The Honda S90 Super 90 typically produces around 8 horsepower from its 90cc single-cylinder, four-stroke engine. This allowed for a top speed of up to 65 mph, making it quite spirited for its size.

What is the top speed of a Honda S90?

When ridden by a lighter individual, the Honda S90 can achieve a top speed of approximately 65 miles per hour (105 km/h).

What is a rotary transmission, and did the S90 have one?

A rotary transmission is a type of gearbox where you can shift 'through' the top gear to reach neutral, and then access first or fourth gear again. It's designed to make stopping and restarting easier by avoiding the need to downshift through every gear. The Honda S90 typically had a standard sequential 4-speed manual transmission. However, the very similar Honda Benly 90 often featured a rotary transmission, which is a key distinguishing feature between the two models.

What kind of engine does a Honda ST90 have?

The Honda ST90 Sport Trail is powered by a single-cylinder, air-cooled 89cc engine with a single overhead cam (SOHC) operating two valves. This engine is paired with a three-speed semi-automatic transmission and a centrifugal clutch.

Is the Honda ST90 a good off-road bike?

The Honda ST90 was designed with a focus on off-road riding, making it a capable entry-level trail bike. It features engine protection, increased ground clearance, higher fenders, and knobby tyres, all optimising it for unpaved terrain. Its low weight and semi-automatic transmission also make it easy to handle for both younger riders and adults.

Why was the Honda ST90 discontinued?

The Honda ST90 had a short production run from 1973 to 1975 because it failed to attract strong sales. It was not sufficiently differentiated from other similar models in Honda's lineup, particularly the popular CT90, leading to its discontinuation.

When was the Honda S90 Super 90 produced?

The Honda S90 Super 90 was produced between the years of 1964 and 1969.

What is a 'Postie Bike'?

The term 'Postie Bike' is commonly used in Australia to refer to the Honda CT110. This model became famous because it was widely used by postal workers for mail delivery, known for its incredible reliability and durability in all weather conditions.

Conclusion

The Honda S90 and ST90, along with their close relatives like the Benly 90 and CT90, represent the ingenuity and foresight of Honda in the mid-20th century. These 90cc machines, whether designed for economical commuting or rugged trail riding, showcased Honda's ability to produce reliable, efficient, and enjoyable motorcycles for the masses. Their legacy continues to thrive through a passionate community of owners and enthusiasts, cementing their status as true classics in the world of two-wheeled transport. For anyone looking to experience the pure joy of vintage motorcycling, these iconic 90cc Hondas offer an accessible and immensely rewarding journey back in time.

If you want to read more articles similar to Honda S90 & ST90: Power, Pedigree & Practicality, you can visit the Motorcycles category.