In the car world, six cylinder engines have long been renowned for their blend of power and smoothness.
Over the years, we’ve seen a fair few attempts at putting sixes in motorcycles too. Six cylinder racing bikes from Honda and Laverda are steeped in legend, and although costly to build and often difficult to install in a motorbike chassis, there have been quite a few flagship sixes over the years.
But what are the best? Intrigued by the launch of the latest Horex VR6 (which is pictured above, but not officially available in the UK) at the recent Intermot show, we at Insidebikes decided to raid the archives and find our top five six-cylinder road bikes. Here they are…
First introduced in 1973, the Benelli Sei (Italian for Six) was the world’s first production six cylinder machine and arguably the company’s greatest road bike.
The Sei was introduced under the ownership of Argentinian industrialist Alejandro de Tomaso (who also owned Moto Guzzi and his eponymous supercar brand) who made a strategic decision to produce multi-cylinder designs designed to take on the emerging Japanese competitors.
The four-cylinder designs owed much to Honda, but it was the 750cc Sei that briefly elevated Benelli to top dog status in the superbike world.
Styled by Ghia, the famed Italian car designers, and Sei introduced the angular lines that would become the norm for Italian bikes of the era. The Sei tacked two cylinders on the end of Benelli’s four-pot designs but with the alternator tucked way behind the engine, rather than on the end of the crankshaft, it wasn’t that much wider or heavier than the 750 fours of the era.
Power was over 75bhp and top speed in excess of 120mph. In 1979 the engine was increased to 900cc, but unfortunately the never ending build quality problems that plagued Italian bikes of the time gave the Benelli a bad reputation and the company closed its doors in 1988.
Over the years, Kawasaki has gained quite a reputation for building road bikes that take performance to a new level. Back in 1972, they did it with the iconic Z1. Then there was the ZZR1100 of the Nineties and, more recently, the supercharged Ninja H2. But in the 1980s, there was this – the 120bhp, six-cylinder Z1300.
Released in 1979, the shaft-driven Z1300 was a massive brute of a bike. Weighing in at over 310kg and wide as a bus, the big Z was never renowned for its handling but with a 140mph top speed and bar room bragging rights the Z1300 gained a cult following in a 10 year production run.
Honda had quite a reputation for building screaming six-cylinder race bikes in the 1960s, but the 1047cc CBX of 1978 was their first attempt at a roadster with such a configuration.
The CBX followed the aforementioned Benelli Sei in using the six as a sportsbike engine (subsequent sixes have usually been aimed at a more touring audience) and it was well received upon reception.
Despite garnering good press reviews, the CBX never sold all that well. The cheaper four-cylinder CB900F outsold the CBX and, after two years in the range, the six was given a redesign to make it more touring orientated.
Honda detuned the engine slightly (from 105bhp to 100bhp) and gave the CBX chunkier air-assisted front forks, monoshock rear suspension, a half fairing and panniers in 1981, arguably creating the sports tourer category, but despite being a very competent motorcycle it found itself out of the Honda range for 1983 as the company decided to focus on building four-cylinder machines.
Arguably the most successful six, certainly in terms of longevity, Honda’s iconic GoldWing has always featured ‘boxer’ engines and in 1987 the fully-dressed tourer switched from a flat four to flat six design – a configuration it has retained right through to this year’s sixth generation model.
There’s little to be said about the ‘Wing that hasn’t been said many times before. The sofa like seat, massive luggage capacity and wind cheating fairing grab the headlines, but away from the headlines that 1833cc six quietly plays an integral role in making the GoldWing the legend it undoubtedly is.
The latest incarnation makes 125bhp, but more importantly a huge 170Nm of torque. That power goes through a trick seven speed DCT gearbox and, while the 383kg GoldWing is clearly no lightweight, the engine’s horizontally opposed cylinders keep the mass lowdown and make the big tourer more manageable than ever before.
With their reputation for making creamy smooth inline six-cylinder car engines, it was hardly a surprise that BMW came up with a six for their flagship tourer, the K1600GT, in 2011.
The Bavarian company had teased the idea with the Concept 6 showbike in 2009, and the final production machine used a 160bhp version of the transversely mounted, 1649cc, motor, which (at 560mm wide) claimed to be the narrowest inline six ever built.
If anything, it’s just a shame that big touring bikes are a real niche sector, because the K1600 engine is epic. Maybe one day BMW will fit the engine to a CBX or Z1300 style naked and give more motorcyclists an opportunity to sample one of biking’s all time great powerplants.
For now, the K1600 remains a tour de force in the touring bike world. And definitely something all riders should try at least once in their lives.
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