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20 Apr 2015 | Author: | Comments Off on BENELLI Find the Latest News on BENELLI at The Art of Motorcycles
Benelli 125 SE

CBX, Z1300, Sei – The Six Pack Trio

The 70s saw something or had something which was never replicated on any era previous or later to it. It was in the 70s that Benelli, Honda and Kawasaki released 6 cylinder engines for mass production. 6 cylinders were something never heard of before the mid 60s and even now, barring the Honda offspring like Rune, Goldwing or the prototype Evo6it is difficult remember any machine with 6 cylinders.

And way back in the 70s, people had a choice of 3 superb engineered machines.

Of course, the most famous of the trio was the HONDA CBX, a bike as legendary as the brand itself. Honda came to the world in full flow in the early 60s and had established themselves with the CB series, the 750, 550, 400-Four and the likes. But through the late 60s and early 70s, Honda didn’t do much except giving newer versions of the same bikes. There was nothing new, in fact Honda was known for innovations, but these years, Honda was up to nothing.

Or was it?

Mr. Tadashi Kume, the then Director of Honda Research and Development knew the unrest among Honda and in general motorcycle fans.

There were rumours speculating and everyone knew that Honda was upto something, but nobody had any clue as to what it is. So Kume then released it… the world’s fastest bike ever produced, the Big Daddy of all, a brute 1047cc, 24 valve with four overhead camshaft, the CBX-Six. The bike was Godzilla fast.

The letters CB followed by a bigger X became known all over the motorcycling world as a must-have commodity, the bike to own and certainly the bike to ride. This was a standard everyday bike which was an excellent tourer, very very fast and all sorts of things you would have wanted in a bike in the 70s. This was ‘it’.

Critics revved its technical credentials, the masses lapped it left and right.

So how did it come into production? Well, Honda had their 250cc and 300cc 6 cylinder GP race engines designed by Shoichiro Irimajiri. He was the project leader of the CBX and believe it or not, he had designed a 2 stroke bike (of course GP spec) which went all the way up to 23000 rpm from its puny 50cc engine!

He also designed a 125cc five. At those times Yamaha and Suzuki were ruling the charts with the killer 2 strokers and to be competitive, Honda had to bring in the 5 and 6 cylinder bikes. The CBX-Six is a direct descendent of those race engines. So, the CBX took only 18 months for production. But the results initially showed that Honda has been rather too quick.

There were issues but the world knew that the CBX is going to be the one bike which will turn on a new era in motorcycling.

The CBX in the prototype stage had 2 models the one which came out and another with four cylinders which was also had a 1000cc motor. The in-line four produced 98 horses inside compared to 103 (measured at the crankshaft) for what eventually came out. So why was the 6 preferred? Simple because it sounded good. Actually, because since the engine size was same, obviously the 6 would have a better delivery of power.

And of course, it sounded good!

Okay, now how to fit the massive engine? Irimajiri bought Norimoto Otsuka (Honda’s Chief Designer for Honda motorcycles sold in North America and Europe) on board. Lots of thinking, engines tilting forward, need of cornering clearance as it being a high-performance sporting bike and all, the CBX fought through all these.

What came out was something exceptional. The bike was blindingly fast, but it was so smooth, that one won’t even notice it if not for the speedometer. The torque was even and linear. It was capable of very high speed handling and remember! this was not a sports bike, but rather a standard road bike.

The point is that it was capable of everything.

Extremely comfortable seats, easy handlebars and there was even a covered fuse box mounted on the top triple clamp. Lots of power from the big engine and thanks to the in-line 6, there was no mentionable vibration. But it never made the rider forget that it is indeed a big heavy bike.

So it also needed an experienced rider. Well, Honda had that thing in mind that the CBX was meant for experienced riders. You can well imagine how big the engine will be and corners are not going to be easy… but actually Honda thought about that too.

You see, when 1000cc is released by 6 engines instead of 4, the engine sizes are smaller and by law of physics, a Six with a three-into-one exhaust can get by with smaller, lighter mufflers than a comparable Four, and smaller mufflers have less of a chance to drag the ground than larger ones. To reduce weight of the bike, some of the essentials were made of aluminum like triple clamps, spoke wheels or plastic like the front fender, had tubeless tires, wet sump instead of dry sump, etc.

Okay, we all know about the CBX more or less, right, so let’s get to some interesting and relevant stuff. The front brakes were of entirely another world. As mentioned Honda knew that by and large, the Honda CBX would be bought by experienced riders, the lightweight, 5mm-thick front rotors are from the GLl000; the rear rotor is unique to the CBX and has been thoroughly trimmed for lightness. Front calipers are from the 750, the rear is the same as the GL’s.

What makes the CBX’s front brake unique is its extraordinarily powerful, light action. A very interesting thing is that initially, the Honda engineers spent days at a air base center in Japan recording the sound of Phantom jet fighters and then replicated the exact sound on the CBX. But later Mr.

Kume rejected Irimajiri’s concept and the exhaust note was changed to make a more Porsche like sound! On the performance front, it is a fact that the bike can accelerate uphill from 15 mph in fifth gear without a hitch and just like that, it can twitch and turn in mountain roads like a 400 pound bike when it tipped the scales at almost 600 pounds.

It had its shortcomings, well if you can call them that, you see, it was kind of a guzzler 35mpg, but that was expected, the other thing was that your mechanic would not really like fiddling with 24 valves each time you wanted a thorough service or he won’t like re-synchronizing the six carburetors either. Such a massive bike with extraordinary front brakes also meant frequent tyre changing, but the fact is you knew what you are getting into, there were no surprises and probably for all these reasons, Honda expected the CBX buyers to be the mature experienced type. All in all, here was ‘the’ bike, devastating engine performance, brilliant high-speed handling, great cornering capabilities for a bike of this stature and many a critics has compared it to GP bikes, but why not, after all it was derived from one!

Engine – 1047cc, Air cooled, four stroke, transverse six cylinder. DOHC, 4 valves per cylinder

Bore x Stroke – 64.5 x 53.4 mm

Compression Ratio – 9.3:1

Max Power Torque -85hp @ 9000 rpm 52.27 lbs/ft @ 6500 rpm

Dry-Weight – 247 kg

Consumption average – 39 mpg

Top Speed – 218.8 km/h

And then what we have here! First thing is that it is a KAWASAKI. Once you really realize that, you know now what to expect.

Yes, Kawasaki has made a name for itself in making the fastest bikes like the H1, K2 750 and the Z900, so it was upto their reputation to keep it. Actually Kawasaki wanted something to beat the CBX, so it made the K 1300 with everything big. It had more power, higher top speed. weighed more, was bigger and costlier but in making everything big, the big Honda got an advantage of easier handling, something very necessary in big bikes.

But for what it was/ is, the Kawasaki K 1300 was the uncrowned king of the streets. Work on the K1300 started as early as 1973 and the motto was to bring back the ‘fastest bike’ title to Kawasaki. It was that simple.

It was all in the drawing board that the new or future king would have at least a 1200cc engine with 6 cylinders. Work began and later it was found out that due to the sheer mass of the proposed bike, the engine size has to be increased and so it was increased a further 86cc and at the time of launch, they named it as Z 1300. Of course, during the making the sheer, as mentioned even in the CBX case, was a problem and here it was even a bigger engine.

The size limits cornering and not to mention the incoming wind thrust. So the option was having a water cooling unit which would also give the provision of diminishing the width in between the cylinders. This would drastically cut the total width of the total engine. Another advantage of water cooling is that it provides good sound insulation and this well-balanced six is notably quiet and smooth with few peers in this respect.

And of course, to cut the wind, it could also be fully faired now although that was not selected as an option as it would have taken away the ‘street-bike’ tag. There was another difficulty and it was in accommodating the customary one carburetor for each cylinder, so the decision was made to use three twin-choke constant-vacuum carburetors which resulted more compact and fitted underneath the fuel tank without impeding the rider.

Power is transmitted through a five-speed gearbox to a shaft drive, mounted on the right-hand side of the bike. For a machine of this size with 120 hp, chain drive would not be a good option. And even to stop this machine, 2 disc are just not enough, so it got three with one in the rear.

The bike is capable to a top whack of 135 mph in top gear with a little more to come at the expense of entering the red zone at the rpm meter. The quarter mile is easily achieved in 11 seconds. Very good figures for a non-sports bike. It has a comfortable saddle which means (as mentioned) you can take it for tours.

Kawasaki achieved at what it intended to, the fastest bike on the streets or to put it in their way, ‘the king of the streets’.

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