Six Cylinder Motorcycle Guide
If enough is good, more is better. A look at Six Cylinder Motorcycles from the 60’s to the future.
Six Cylinder Motorcycles
One of the great things about motorcycles is that riders usually prefer to talk about performance and technical aspects over the appearance. Function over form. Like most things, more is better. More horsepower, more valves, more cams. And more cylinders.
The performance kings of the motorcycle world have often had 4 cylinders, but there’s been some notable sixes.
We take a look at some landmark six bangers.
Honda RC166 250 GP Racer
In the early sixties, Honda was locked in a GP battle with other makers two stroke machines. Several multi cylinder machines of various sizes were made, but one of the most dramatic and well remembered is the six cylinder 250.
Shown here is the RC166, the 1966 version that won 10 out of 10 races in the 1966 World Championship. The RC166 also won the Manufacturers’ and Riders’ Championships in the 250cc class for two consecutive years, as well as the Isle of Man TT.
These fascinating machines could fill an entire page with engineering detail – 6 pistons, 4 cams, 24 valves, and an 8 speed gearbox. This little jewel made a staggering 60 horsepower at an ear shattering 18,000 revs.
In the early 70’s, Italian manufacturer Benelli released the “Sei”, an imaginatively named 6 cylinder road bike. The 750cc motor was basically a Honda CB500 design with a couple of extra cylinders added on.
I rode one of these back in the late 70’s, my recollection is of a very smooth and great sounding bike, but somewhat disappointing power. Benelli upped the capacity to 900cc before the machine went out of production. Possibly the greatest set of standard exhaust pipes ever offered on a motorcycle.
Honda waited a bit longer to draw on their six cylinder experience, but when they did, what a machine. The 1979 CBX1000 not only had six cylinders, but by utilising the motor as a stressed member of the frame, it exposed the entire front of that beautiful wide engine and it’s gleaming six chrome headers.
Making around 100 horsepower, it was the equal of it’s four cylinder competition, but at 270 odd kilograms, fell short in the performance stakes.
The suspension wasn’t as good as the engine however, and perhaps with the sheer audacity of the engineering Honda used, 24 valves developed more in the way of servicing fears than selling points, when compared to it’s 8 valve competitors.
I rode several of these at the time, whilst owning a new GS1000 Suzuki. Power felt a little less, but was smoother and again, that fantastic six cylinder sound. One example I rode was fitted with a six into six open megaphone exhaust, the like of which I have never heard the equal.
Late 70’s and Kawasaki fans were excited to hear that the big green K were releasing a 1300cc six cylinder monster. Z1 owners everywhere couldn’t wait to see the new machine which many felt would put Kawasaki back at the top of the performance charts the Z1 led in 1973.
It was a monster all right, over 700lbs of it! Bulging with liquid cooling, shaft drive and an engine loaded with balancers and dampers, the massive Z1300 was more a tourer than sportsbike. The unbelievably complex engine – it had a harmonic balancer for example- put out a decent 120 horsepower, but the twin pipes muffled the six roar to a whistle, and other than those who bought one, I recall few fans.
My memories of the few brief rides I had on this model are from when they were new. Lots of power, silky smooth, but just a massive lump of a bike. I would love to ride one now to compare. Whilst I couldn’t find any substantiating figures, I don’t recall it being a big seller in Australia, however it did last most of the way through the 80’s in various guises in the USA.
Honda Gold Wing
The Honda Gold Wing six differs from the motorcycles above, with a flat six boxer style engine, rather than the more spectacular straight six arrangement. From its start as a flat 4 1000cc in 1975, by the late 80’s the Wing had grown to a 1500cc six.
Much can be written about the Gold Wing which has cemented itself as the standard for this style of motorcycle, but it would be mainly about touring capability. The current model is up to 1800cc, with about 120 horsepower. The flat six engine doesn’t produce the same evocative sound as an inline, with smoothness now being it biggest asset.
BMW are about to release a six cylinder motorcycle. No surprise that it will be an inline six, given BMW’s long history with that style of engine in performance cars. The upcoming K1600GT and GTL models will thump out a healthy 160 horsepower according to BMW’s press releases.
Available in two models the “Dynamic touring” GT and the “Luxury touring” GTL, the K1600s will be dripping with high tech features. Look for an upcoming feature on these new era sixes.
Six Cylinders into the Future.
Here is a trio of six cylinder concept bikes which may or may not see the light of day at your local dealer.
Suzuki Stratosphere – 1100cc, 24 valve inline six. 180 horsepower. Suzuki fans are keeping their fingers crossed that this Katana influenced six pot becomes a reality.
Honda EVO 6 – A “muscle” bike based on the 1800cc flat six engine of the Gold Wing, with naked street cruiser styling. Probably aimed at the Rocket3 / VMax market, the EVO6 is rumoured to make it into production. Let’s wait and see.
The best set of exhaust pipes this century mark BMW’s Concept6, which BMW say is their idea of a modern day “cafe racer”. As this engine will be making it to production in the K1600 tourer, it’s possible something like this will hit the showroom. Here’s hoping! Imagine the noise those side pipes would make.
More info on this bike is here in our Concept6 story.