The Bonneville Saga: From '77 T140 to 2020 T120

The Triumph Bonneville, a name synonymous with British motorcycling heritage, has captivated riders for decades. From its humble beginnings to its modern resurgence, the Bonneville has undergone significant transformations, often reflecting the changing fortunes and technological advancements of its manufacturer. This article delves into key moments of its storied past, examining the challenges faced by the 1977 T140, the distinctive features of the 1979 T140D, and the powerful heart beating within the 2020 T120, offering a comprehensive look at how this icon has evolved.

The 1977 Triumph Bonneville T140: A Period of Austerity

As the 1977 model year dawned, the Meriden Co-op, the worker-led entity that had taken over Triumph's motorcycle production, found itself in a precarious financial position. Operating on a shoestring budget, the company was forced to make difficult decisions regarding its product line. The formidable T160 Trident had already been discontinued in 1975, and now the 650cc T120 and TR6 series were also dropped. The focus was narrowed to a single engine platform: the 750cc twin, available in the T140 Bonneville and the TR7 Tiger forms.

For 1977, the Bonneville lineup featured two distinct models: the standard Triumph T140V Bonneville and a special, limited-edition factory custom known as the Triumph Bonneville T140 Silver Jubilee. The 'V' in the T140V designation signified a 5-speed gearbox, a feature that was standard across all models. The Silver Jubilee, marked by a 'J' suffix (T140VJ), was conceived to commemorate the 25th (Silver) Anniversary of Queen Elizabeth II's reign. Production for the model year commenced with Engine #GP75000.

Carry-Over and Cosmetic Flair

Due to the severe budget constraints, the 1977 Triumph T140 Bonneville saw very few mechanical updates. It was, in essence, a direct carry-over from the 1976 model, which itself was a carry-over from 1975, and that from 1974. This meant that, apart from the US-mandated switch to a left-hand gear shift, the basic Bonneville had remained largely unchanged and unimproved for four consecutive model years – an almost unheard-of duration in the rapidly evolving motorcycle industry of that era.

The significant changes for 1977 were almost exclusively reserved for the Silver Jubilee model, and these were purely cosmetic. The outer engine covers – including the primary, timing, and gearbox covers – were chromed, adding a touch of sparkle. The Jubilee's paint scheme was unique: a striking Silver over Blue with Red pinstriping, evoking the colours of the British Union Jack flag. This patriotic theme extended to the seat, which featured blue vinyl with red piping. The Jubilee also received special 'upside-down' Girling rear shocks with exposed springs and a generous application of chrome, further distinguishing it from the standard Bonnie.

The stepped seat design, though flamboyant in its Jubilee colours, set a precedent, becoming the pattern for almost every Bonneville seat thereafter. Interestingly, the Jubilee maintained the regional tank distinctions: US-bound bikes continued with the slimline tanks, while UK models retained the larger-capacity, boxy British-spec tanks. New side covers were adorned with special Silver Jubilee emblems, proudly displaying "1977" and the red, white, and blue Union Jack.

Production and Impact

The initial plan for the Silver Jubilee was to produce 1,000 units for the home market to honour the Queen. However, their popularity led Meriden to quickly assemble another 1,000-unit run for the lucrative US market, followed by an additional batch of approximately 400 for general export. Early side cover emblems read "One of a Thousand," but once production exceeded this, subsequent bikes were wisely labelled "Limited Edition."

Despite the respectable sales of around 2,400 extra units, the Silver Jubilee wasn't enough to fundamentally alter Triumph Motorcycles' fortunes. It wasn't faster or technologically superior; it was, at its core, an appearance package. Moreover, its flamboyant aesthetics were not universally loved, with many finding its look "too garish." Nevertheless, the Silver Jubilee's true significance lay in its pioneering role: it was the first in a series of special, limited-edition factory customs that Triumph would produce over the next few years. While not a company saviour, this strategy arguably prolonged the inevitable for a while longer, giving rise to some truly cool classic British motorcycles.

Table 1: 1977 Triumph Bonneville T140V vs. T140 Silver Jubilee (T140VJ)

The 1979 Triumph T140D Bonneville Special: A Bold Redux

Two years after the Silver Jubilee, Triumph introduced another distinctive model: the 1979 Triumph T140D Bonneville Special. This model represented one of Triumph's most significant cosmetic and partial mechanical revamps of the classic T140 Bonneville. While it certainly looked the part, the changes weren't merely skin deep, although some had unintended consequences.

The T140D borrowed elements from its Jubilee predecessor, featuring the familiar 'upside-down' Girling shocks. However, it distinguished itself with a unique two-into-one exhaust header and, most notably, stunning Morris mag wheels. These cast alloy wheels gave the bike a thoroughly modern and aggressive stance, setting it apart from the more traditional spoked wheels of other Bonnevilles.

Under the bonnet, the engine saw modifications primarily driven by the increasing demand for emissions reduction. The T140D, like all 1979 Bonnevilles, received a new 'smogger' cylinder head and Amal Mk II carburettors. While the new exhaust header theoretically offered power gains, these were largely negated by the emissions-focused engine changes. Compression was also reduced to a modest 7.9:1, an attempt to lessen engine vibration, though this further contributed to a perception of reduced power output.

A significant technological update for all 1979 Bonnevilles was the introduction of Lucas's new 'Rtia' electronic ignition system, aiming for improved reliability and starting.

Distinctive Aesthetics and Riding Experience

The T140D Bonneville Special was instantly recognisable by its striking all-black paint scheme, elegantly highlighted with gold pinstripes. This monochromatic look, combined with the distinctive 2-into-1 exhaust and those eye-catching Morris mag wheels, clearly set it apart from the standard T140E Bonnevilles of the era. While primarily black, a rare blue and silver colour combination was also available, though few were produced.

From a rider's perspective, the T140D was generally considered a decent bike to ride, albeit with some quirks. The stepped seat, while visually appealing, wasn't renowned for its long-distance comfort. Power output was modest, and the 'smog-era' carburettors could be finicky, both to tune and in their on-road behaviour. The 2-into-1 header, while a design statement, wasn't always praised for its exhaust note, with many preferring the sound of traditional dual pipes. Despite these minor drawbacks, the T140D was undeniably a handsome machine and performed fairly well in the marketplace, further cementing Triumph's presence and ensuring that many T140D models are still seen at auctions and shows today.

Table 2: Key Distinctions: 1979 T140D Bonneville Special

The Modern Era: 2020 Triumph Bonneville T120 Engine and Evolution

In the contemporary motorcycle landscape, where vintage style meets modern performance, the Triumph Bonneville stands as a prime example. While its journey has been punctuated by periods of struggle and hiatus, its return in the 21st century has been nothing short of triumphant, inspiring a whole host of 'neo-classic' motorcycles.

The Bonneville's origins trace back to 1959, born from American demand for more power than Triumph's existing 650cc Tiger T110 could provide. The solution was simple yet effective: add another carburettor, thus creating the iconic 1959 Bonneville T120. The original 'Meriden Bonnevilles' were produced from 1959 to 1983, with the 1963-1970 models, featuring redesigned 650cc air-cooled two-cylinder engines and frames, often cited as the most beloved.

Later iterations, such as the 1970s T140s, saw the introduction of front disc brakes, eventually evolving to full discs and an electric starter by the end of their initial production run. After a multi-decade absence, Triumph boldly resurrected the Bonneville name in 2001. A significant update in 2016 brought forth its current forms, the T120 and T100, which offer a compelling blend of classic aesthetics and contemporary technology.

The Heart of the 2020 T120

Comparing the past to the present, the evolution of the Bonneville's engine is remarkable. While a 1970 Bonneville's 650cc two-cylinder engine produced around 49 hp, the 2020 Triumph Bonneville T120 boasts a considerably more potent powerplant: a 1200cc fuel-injected water-cooled two-cylinder engine. This modern marvel is rated at a robust 80 hp and 77 lb-ft of torque, delivered through a smooth 6-speed transmission.

Beyond sheer power, the modern T120 is laden with technological advancements that were unimaginable in its classic forebears. It comes equipped with front and rear ABS-equipped disc brakes, traction control, cruise control, and multiple riding modes to suit varying conditions and rider preferences. The instrumentation combines an analog speedometer and tachometer with a practical LCD display, offering a fuel gauge, gear indicator, and even heated grips for colder rides. However, one notable difference remains: the classic bikes are often over 100 pounds lighter, contributing to a distinct riding feel.

Riding Experience and Reliability: Classic vs. Modern

Despite their age, classic Triumph Bonnevilles can still provide an immensely enjoyable riding experience on modern roads. Their relatively light curb weight makes them approachable and unintimidating, often falling between the weight of modern smaller-displacement bikes. While their drum brakes may not offer the same stopping power as discs, they are generally adequate, and the transmission is typically easy to shift. However, owning a classic Bonneville often entails a degree of "tinkering," a charming aspect for some, a constant chore for others.

In contrast, the newest Triumph Bonneville T120 is often described as "almost fault-less." While heavier than its classic counterpart and with a larger engine that might initially intimidate newer riders, its clutch is easy to modulate, as are the brakes and throttle. The handling is universally praised as excellent, offering a refined and confident ride. For those concerned about the 1200cc engine's size, the 900cc, 5-speed Bonneville T100 offers a more approachable package, delivering 55 hp and 59 lb-ft, and sharing many of the T120's strengths, albeit without standard heated grips, riding modes, or cruise control.

When it comes to reliability, the modern Triumph Bonneville significantly outclasses its classic ancestors. Classic motorcycles, by their very nature, are less reliable than modern machines. Older bikes are prone to frayed cables, cracked rubber components, and leaks, not to mention shorter maintenance schedules. Classic Bonnevilles, in particular, gained a reputation for leaking fluids, a problem exacerbated in post-1971 models that stored engine oil in their frames, leading to oil foaming and decreased supply. The notorious Lucas electrics also contributed to unreliability, and the practice of shipping British motorcycles unassembled often led to quality-control issues that were rarely covered by warranty.

While the modern Bonneville is not entirely immune to quality issues (some owners report water in gauges, squealing brakes, and there was a 2019 wiring harness recall, plus pre-2019 shifter spring issues that have since been addressed), these problems are far less frequent and generally less severe than those faced by classic owners. The choice between classic and modern often boils down to a preference for a hands-on, authentic experience versus a bike you can simply "get on and ride."

Pricing and Value

Interestingly, classic Triumph Bonnevilles are not necessarily significantly cheaper than their modern counterparts today. A 2020 Bonneville T120 starts around £9,500 (approx. $11,850 USD), with the T100 starting closer to £8,500 (approx. $10,450 USD). Meanwhile, while some 1970-and-earlier classic Bonnevilles might sell for around £6,500 (approx. $8,000 USD), many desirable examples can fetch between £8,000 and £12,000 (approx. $10,000-$15,000 USD) or even more, depending on condition and rarity.

Table 3: Classic vs. Modern Triumph Bonneville (General Comparison)

Table 4: 2020 Triumph Bonneville T120 vs. T100

Frequently Asked Questions (FAQs)

Q: Why was the 1977 Triumph T140 Silver Jubilee significant?

A: The 1977 T140 Silver Jubilee was significant not for its sales volume or technological advancements, but because it was the first in a series of special, limited-edition factory customs that Triumph would produce. This strategy helped to prolong the company's existence during challenging financial times, paving the way for future distinctive models.

Q: What were the main differences in the 1979 T140D Bonneville Special?

A: The 1979 T140D Bonneville Special stood out with its all-black paint scheme with gold pinstripes, Morris mag wheels, and a two-into-one exhaust header. Mechanically, it featured the Silver Jubilee's upside-down shocks and shared the 'smogger' cylinder head, Amal Mk II carbs, and Lucas 'Rtia' electronic ignition with other 1979 Bonnevilles.

Q: How does the engine of the 2020 Triumph Bonneville T120 differ from classic Bonnevilles?

A: The 2020 Triumph Bonneville T120 features a modern 1200cc fuel-injected water-cooled two-cylinder engine, producing 80 hp and 77 lb-ft of torque. This is a significant upgrade from classic Bonnevilles, which typically had air-cooled, carburetted 650cc or 750cc engines with lower horsepower outputs (e.g., ~49 hp for a 650cc).

Q: Are classic Triumph Bonnevilles reliable?

A: Classic Triumph Bonnevilles are generally less reliable than modern bikes. They are known for issues such as fluid leaks (especially post-1971 'oil-in-frame' models), problematic Lucas electrical systems, and quality control issues from being shipped unassembled. They often require more frequent maintenance and 'tinkering' compared to their modern counterparts.

Q: Is a modern Bonneville better than a classic one?

A: Whether a modern Bonneville is 'better' depends on individual preference. Modern Bonnevilles offer superior reliability, performance, and advanced features like ABS, traction control, and riding modes, making them ideal for everyday riding. Classic Bonnevilles offer an authentic, raw riding experience and historical charm, but demand more maintenance and a tolerance for their quirks. Neither is definitively 'better'; they simply offer different experiences.

The Triumph Bonneville's journey from the financially strained days of the Meriden Co-op and its carry-over models like the 1977 T140, through the distinctive design choices of the 1979 T140D with its Morris mag wheels, to the sophisticated power of the 2020 T120's 1200cc fuel-injected water-cooled two-cylinder engine, is a testament to its enduring appeal and the brand's resilience. It's a narrative of adaptation, survival, and ultimately, a triumphant return to global prominence. Whether one prefers the raw, hands-on charm of a classic or the refined, technologically advanced ride of a modern machine, the Bonneville continues to hold a special place in the hearts of motorcyclists, embodying the spirit of British motorcycling heritage.

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