Honda CBX, Kawasaki KZ1300, Benelli 900 Sei, Six-Cylinder Classics | Cycle World

Six-Cylinder Classics: Benelli 900 Sei, Honda CBX, and Kawasaki KZ1300

Imposing girth, incomparable voice and effortless sophistication

Benelli 900 Sei, Honda CBX, and Kawasaki KZ1300

Honda CBX, Benelli 900 Sei, and Kawasaki KZ1300.

Marc Urbano

"Have you ever ridden a Honda CBX?” a gentleman named Joe Bortz asked me over the phone a few weeks ago.

“Why, yes,” I said, feeling suddenly more ancient than usual. “I wrote the Cycle World road test on the 1981 CBX. The silver version, with the fairing and bags. That’s me on the cover of the magazine, leaned over to the footpegs.”

“Ah,” he said. “Well, have you ever ridden any of the other big Sixes from that era–the Benelli 900 Sei or the Kawasaki KZ1300?”

“No,” I admitted. “I sat on a KZ once, but I don’t believe I’ve ever even seen a Benelli 900 Sei outside of a museum.”

“Well, I have all three in my little motorcycle collection here in suburban Chicago,” Bortz told me. “You should come down from Wisconsin and do a story…”

And so it came to pass that three of us from CW converged on an industrial park in Deerfield, Illinois, where Mr. Bortz keeps his bikes–about 30 of them.

Some folks collect motorcycles by brand or nationality or engine type, but Joe says he gathers them in sets. Sixes from the late Seventies and early Eighties; GSX-Rs from the earliest to the latest; Japanese turbo bikes of the Eighties, all known Square Fours and so on.

Benelli 900 Sei, Honda CBX, and Kawasaki KZ1300

Benelli 900 Sei, Honda CBX, and Kawasaki KZ1300.

Marc Urbano

“I rode a lot when I was young,” he said. “I installed a Travis motor kit on my J.C. Higgins bicycle when I was 10, and then I got a used Whizzer Pacemaker and moved up to a 250cc NSU Max and put 25,000 miles on that bike in two years. But then I went to school and got involved in my career and got away from riding.”

He became a biochemist and worked for a pharmaceutical company, then struck out on his own and ran a successful chain of restaurants and bars. When the money started rolling in, he began collecting cars–mostly dream and concept cars from auto shows.

But just three years ago, during recuperation from surgery, Bortz started looking at used motorcycles on the Internet and caught bike fever again. “I was astounded at the number of historically significant and technically interesting bikes you can find–at a fraction of collector car prices,” he explained. Joe bought a tank-shift Indian Four to start the ball rolling, and the rest is…more and more history. Now his warehouse is nearly full.

With the help of his sometime-mechanic and tuner Mike McKeon, Bortz wheeled his three jewels into the Sunday-morning sunlight. They were: 1) A 1981 Benelli 900 Sei (pronounced Say, Italian for “six”) with 31,000 kilometers on the clock, bought on eBay from a German leaving California for home; 2) a 1979 Honda CBX, also bought on eBay–with a matching helmet, no less–showing 9700 miles on the odometer; and 3) a 1979 Kawasaki KZ1300 (“another eBay purchase from…somewhere”) with 10,572 accumulated miles.

Three classics, from the Age of Optimism, when anything was possible. This is right when I came into the business–joining CW as Technical Editor in 1980. Japanese technology was flying high, bike sales were breaking records every year, and “old designs” such as the BMW Boxer Twin and the quaking Harley V-Twin were widely believed to be on their way into the dustbin of History. Things were getting ever smoother, better and more sophisticated.


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Benelli was the first company to introduce a six-cylinder road-burner in the Seventies–the 750 Sei was announced in 1972–but I suppose you could blame Honda for making the world comfortable with long rows of cylinders and carburetors.

It was Honda, after all, that had built the marvelous, shrieking RC166, a 250cc six-cylinder racebike that revved to 17,000 rpm–and was just 14 inches wide. The sight of Hailwood racing with those twin sets of three black, strangely organic pipes fanning out from beneath his boots left a deep impression. In my old Isle of Man recordings, the Honda Six sounds like a police siren going past the pits, and everything else sounds like a 19th-century stamp mill–or the air compressor in my workshop.

“Fine for exotic racebikes,” we all said, “but you’d never be able to keep all those carbs in tune on a streetbike. Look at my Triumph Daytona 500, with just two carbs. The cables are always stretching. Imagine a Six! Madness, I tell you!”

But then Honda brought out its CB750 Four, followed by the CB500, and…nothing bad happened. The carbs stayed in tune, the bikes ran forever (relatively speaking) and the engines were turbine-smooth. The age of toad-hopping engine vibration seemed to be over. Why had we put up with it?

Suddenly, it seemed that complexity exacted no price. Engineers (especially Honda engineers) could make anything they wanted–and they could make it work. The motorcycle world took this all in and said, in collective chorus, “What’s next?”

Strangely, the first person to answer this question was a colorful Argentine entrepreneur named Alejandro de Tomaso, who acquired the legendary, but failing, Benelli motorcycle works in 1971. Anxious to make a marketing splash and put Benelli back on the radar screen, he called the engineers together and said, in so many words, “Make me a large, road-going Six, boys. And make it right now.”

Cycle World August 1974 magazine cover

Benelli 900 Sei on the August 1974 cover of Cycle World.

Cycle World

So they ran straight to their drawing boards and designed a 750 that was nearly an exact copy of a Honda 500 Four–with two extra cylinders. Same bore and stroke, nearly identical castings. When the first pictures came out, I remember gasping at the audacity of this plagiarism and showing them to my friends.

“How can they do this? Isn’t there a law?”

Apparently there wasn’t, and Benelli brought the 750 Sei to the U.S. in 1974, as seen on our August cover of that year. The styling, at least, was decidedly Italian and un-Japanese, and the engine–though not extraordinarily powerful at a claimed 76 bhp–was both smooth and charismatic. It had three Dell’Orto carburetors, each one feeding pairs of cylinders (good for knee room), and those six separate mufflers splayed back at you like ray guns.

In 1979, Benelli increased the bore and stroke to make the Sei a 900, dropped the six pipes for a 6-into-2 system with quieter Silentium mufflers and smoothed out the styling. The bikes began trickling into the U.S. during the early Eighties, but Benelli had a sparse dealer network, and you didn’t see many on the road. In any case, Honda had already struck back, a year earlier, with the ethereal CBX. Our April, 1978, cover called it “The Fastest Bike We’ve Ever Tested,” with a measured top speed of 134 mph.

Designed by legendary racing engineer Shoichiro Irimajiri–who’d designed that famous RC166 250cc Six for Hailwood–the 1047cc, 24-valve, 103-hp Honda Six was a shimmering vision of mechanical complexity and tidy, almost waspish styling. It looked modern, lean and contemporary, with that wide, beautiful engine sticking out as if to say, “Take that!”

Honda advertising showed a coffee cup and a set of CBX keys with a winding road in the background, inviting you to go for a Sunday ride down the canyon. Irresistible.

And yet some of us resisted.

Cycle World July 1981 magazine cover

Honda CBX on the July 1981 cover of Cycle World.

Cycle World

Once you got past the astonishment, it sank in: A Kawasaki KZ1000 or Suzuki GS1000 went nearly as fast and handled better. The CBX weighed 603 pounds, had a slightly squirmy swingarm mounted in nylon bushings and was a bit ponderous on the racetrack–or a backroad. And then it had all those valves to adjust, and carburetors…

I’d owned enough Honda Fours by then to know that sometimes you really did have to take those carbs off–leaking needles and seats, mostly–and it was no fun. And now there were six of them. A man (or a tallish woman) had to think it through before buying a CBX. Many of us admired the bike from a distance, aching to own that engine, but did not buy.

Two years later, to widen the appeal of the CBX, Honda added a very pretty sport-touring fairing and some classy, attaché-case-size saddlebags. Still, the bike did not sell like hotcakes. For 1982, Honda painted the bike white, then afterward let the model drop out of the lineup, after only five years of production.

As mentioned earlier, I wrote the road test on the silver sport-touring version in 1981 and enjoyed riding the thing. It felt long, plush and civilized, and, with the new Pro-Link single-shock swingarm, handled quite well for such a big, wide bike. I seriously considered buying one but eventually bought a Kawasaki KZ1000 Mk. II instead. Smaller, simpler and more versatile. Eddie Lawson, after all, was winning Superbike races on KZ1000s, and nobody in his right mind was racing a CBX. The rabid Boy Racer gene won out over the more mature Gentleman’s Express gene. I was about five years too young for a CBX. Those were the days.

Meanwhile, there was another Six in the showrooms: Kawasaki’s massive, 120-hp KZ1300, also introduced in 1979. If the Sei and CBX were pitched as sportbikes, the KZ had no such pretensions; it was simply The Locomotive. At 710 pounds with fuel, it outweighed the CBX by about 100 pounds, and the Sei by more than 200. Fantastically complex, with liquid cooling and jackshafts and chains everywhere, it was aimed squarely at the long-distance touring market, like an Electra Glide from Alpha Centauri. It begged for a big Vetter Windjammer fairing and aftermarket hard bags.

Which, in most cases, it promptly got. We had it so equipped on the cover of our April, 1979, issue, and in the first road test we dubbed it “A New Kind of Motorcycle: The Luxury Superbike.”

Cycle World April 1979 magazine cover

Kawasaki KZ1300 on the April 1979 cover of Cycle World.

Cycle World

When I arrived at CW in 1980, this test bike had already passed from our grips, so I never got to ride one. When I asked Managing Editor Steve Kimball what he thought of the bike, he just said, “Big.” Many of our readers agreed, and the letter columns were filled with protest that the motorcycle industry had finally gone Too Far. Things were getting ridiculous! Civilization as we know it was doomed, etc.

Nevertheless, the Big KZ developed a loyal niche following and stayed in production for nine years–far longer than the Sei or the CBX. Utility won out: You could pile anything on this baby and ride it to the other coast.

Or, in our case, around the villages of north suburban Chicago, nearly 30 years later. Suddenly, it was time to climb on and sample these three legendary contenders in our little retro shootout. Bortz asked that we keep the mileage and speed down on these pristine, low-mileage babies, so we rode through quiet parks and along the lakefront at moderate speed, gathering impressions rather than test data. But then, that’s what the old road tests, done back in the day, were for. Now is not the time to hammer old bikes. Here’s what we found:

There’s no winner here. These are all great motorcycles, but with distinctly different personalities. The Benelli is the most pure fun—it’s small, visceral and mechanically communicative as only an Italian bike can be. The Honda is simply a grand, complete piece of work, posh and sophisticated, with finely sanded edges. And the Kawasaki is a powerful, solid and rugged road-burner for long miles. A brute, but a surprisingly intelligent and friendly one.

All of them are still handsome, to my eye, and all of them have better seats and a more rational riding position than any contemporary bike I can think of. So much so that if someone had suggested a long road trip to either coast at the end of our little weekend jaunt, I’d have been happy to keep riding. Indefinitely.

There’s just something about the willing, effortless smoothness of an inline-Six that suggests the bike could go on forever and never use itself up. Or you, either. Modern, counterbalanced Fours and Twins can now deliver almost (but not quite) the same smoothness–with even more performance–but they don’t deliver it with the same class and almost operatic sense of presence. These are orchestral bikes in a world of garage bands. Verdi and Puccini would love to have heard them run.

Benelli 900 Sei static rear 3/4 view

Benelli 900 Sei.

Marc Urbano

BENELLI SEI: First Modern Six

When it was time to mount up for the first segment of our ride, I found myself going straight for the Benelli. Why? Well, I’m a person who likes to get the worst over first, and I imagined that the Sei would be a fussy and difficult Italian exotic, with a weird clutch, snatchy driveline, hard seat, no flywheel and offbeat handlebar switches.

Wrong on nearly all counts. By the time I’d been on this bike for 10 minutes, I didn’t care if I ever traded back.

First impression? It’s small and compact, and almost seems smaller than the Honda CB500 from which it derived its mechanical inspiration. More like a CB400F, with a wide motor. Nice flat seat, perfect sport handlebar position, and footpegs unexpectedly conventional and a bit forward, like those on my old RD400. The engine starts with a smooth, glassy whoop that is heard more than felt. At the Italian launch of the 750 Sei, Benelli engineers perched a cigarette, filter end down, on the gas cap and revved the engine. The cigarette didn’t topple over. I think you could still do this on the 900–though having quit smoking years ago, I didn’t try it. Also, cigarettes are too expensive now to waste on experimental science.

A medium-heavy clutch greets your left hand, and it takes a few revs to get going, but once you snick into gear and start rolling, the bike feels silky and agile, with a low center of gravity. The Marzocchi fork and shocks feel taut, but not overly harsh, and there’s a lazy, broad torque band that starts cranking out seamless acceleration from about 2000 rpm, with no herky-jerky power pulses. A straight Six sparks a new combustion stroke every 120 degrees of crank rotation, so the power feed to the Sei’s unusual duplex drive chain is silky and continuous. (Side note: An acquaintance named Marshall Elmer, who used to be a Benelli dealer in Menasha, Wisconsin, told me those two-row chains would last 22,000 miles with proper oiling, and the engines lasted “forever.”)

Turn-in with the Sei seemed intuitive and natural, with no strange steering or cornering habits–though, admittedly, we didn’t lean on it much. But at cruise speed, the Benelli was quite agreeable.

Italian oddities? Just a long reach to the sidestand–which shuts the engine down, even in neutral–and a turnsignal switch with no center detent. Everything else was delightfully normal, hard as that is to believe. I got off saying, “I could own one of these.”

Honda CBX static rear 3/4 view

Honda CBX.

Marc Urbano

HONDA CBX: Born in Grand Prix

I’d ridden all kinds of CBXs before, so I expected no surprises, but the Honda felt tall, high and mighty after the Benelli. Wider, more upright bars; cushier seat, slightly rearset pegs; a little more top-heavy. But it also felt more refined and civilized, the clutch and throttle action having that light, Teflon-lined feel so typical of Hondas, and the suspension soaking up bumps with more aplomb.

More power, too. Everywhere.

The Honda’s 1047cc Six has 141 metric cubes on the Benelli and about 20 more hp, so it shoots itself down the road with less effort–and continues to build shrieking, manic speed as the more docile Benelli decides it’s done enough and settles into humming cruise mode. Where the Sei revs with a raspy, Ferrari-like mechanical sound, the Honda Six woofs and rustles like a perfectly balanced turbine. When you rev the Benelli, you say, “Cool!” and when you rev the Honda, you say, “Lovely!”

You also see a lot more of the Honda engine when you look down, as if riding along and presenting it–in all its glorious width–to the world. Kind of like holding forth a Papal ring, only more fun. The overall finish of the CBX is very high, and the handlebar castings, tank paint and engine finish look quite rich and exquisite. It’s still a stunning and beautiful bike from almost any angle.

At one of our stops, Executive Editor Mark Hoyer said, “The Benelli Sei feels and looks like a vintage bike, a product of the Seventies, but the Honda feels modern, and looks that way, too. The styling doesn’t seem dated.”

Overall, the Honda is a more complete package than the Benelli, but it is big. The Sei is like a conventional Seventies’ motorcycle that happens to have a six-cylinder engine, while the Honda is essentially a stunning engine with a very nice motorcycle designed to carry it around. Almost a creature unto itself.

Kawasaki KZ1300 static front 3/4 view

Kawasaki KZ1300.

Marc Urbano

Kawasaki KZ1300: Long-Distance Six

Ah, here’s The Motor. Tall and smooth, with unfinned sides, built like a crusader fortress. It growls deeply, a whole octave below the other two. There’s a monster down in that dungeon. When Chuck Davis (our third riding volunteer and an old touring buddy) rode it, he got off, grinning, and said, “This is The Beast.” Then he added, “It also has no damping in the fork.”

We’d already been warned about the fork by McKeon, who said he’d had no time to add the correct fork oil in the recently acquired KZ. But that was about its only serious flaw.

The Kawasaki is a big brick of a thing, but not as scandalously large as a previous generation of critics (mine) would have you believe. I guess we’ve become desensitized by the current raft of 700-plus-pound cruisers and tourers, to the point where they’re now about as shocking as people with brown hair. But in 1979 it was a big deal.

There’s a hint of top-heaviness as you get the bike off its side-stand, but once under way, the KZ is unintimidating and easy to ride, with a marvelously comfortable seat from which you can easily plant both feet. Clutch, brakes and throttle all feel like those on any other good motorcycle of the era, and the only unusual element is that deep, bowels-of-the-earth growl from what may be the most flexible engine in all motorcycling. Or professional earthmoving, for that matter. It just pulls effortlessly, without fuss, at any rpm, in any gear, at any time.

And, unlike our other two Sixes, it never feels the least bit hyper. It’s a low-key, muscular tractor motor, but no tractor was ever this smooth. The Kawasaki shares that electrically smooth, feline purr with the Honda and Benelli, but it sounds like a purr coming from a much larger cat.

The big KZ is the only shaft-drive bike in our group, and I suppose it would have some typical period jacking effect if you tried to race it around Willow Springs, but at normal touring speeds it’s a non-issue. This is a bike that really does cry out for a fairing and bags. It’s comfortable and pleasant unadorned, but feels as if it could carry any amount of tonnage without even noticing.

Like the Benelli, the KZ1300 has just three (dual-throat) carburetors, which makes life a little easier for owners and mechanics. But the simplicity ends there, and there are so many shafts, chains, dampers, pumps and cooling-system components that doing a rebuild on a worn-out KZ engine would be daunting indeed. I would be interested to hear if any owner has ever done it.

Suddenly, the appeal of those seemingly once-outdated BMW and Harley Twins snaps into focus.

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