Honda CB400 Four: Less is More

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Don Hughes' 1976 Honda CB400 Four.
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Don Hughes' 1976 Honda CB400F.
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Though the 400 Four sparked the café racer styling trend that would eventually give us today's repli-racer sportbikes, it wasn't universally appreciated at the time.
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Honda CB400 Four
Years produced:
Total production: 105,000 (est.)
Claimed power: 37hp
Top speed: 95mph
Engine type: 408cc overhead cam, air-cooled inline four
Weight (dry): 179kg (394lb)
Price then: $1,470
Price now: $1,800-$3,000
MPG: 45 (period test

More than 30 years later, the Honda CB400 Four has never looked better. A stalwart British bike fan, I’d never ridden a Japanese multi until one day in 1975. My “daily driver” was a persnickety BSA Victor, a worthy enough machine, certainly, but a real clunker. It was, after all, just an old-fashioned and only partially civilized dirt bike.

A friend offers me a ride on his new CB400F. I’m not going to like this, I tell myself. It’s a wussy rice burner. I’m still trying to kid myself that it’s nothing special when I hand it back. Just six years separate the Beezer from the F-bike, but the contrast is huge; it’s like the Space Shuttle just landed in the Stone Age.

I doubt I could have chosen a more stark comparison if I’d tried, and in spite of my own laggardness, by 1975 the rest of the world was used to four-cylinder Hondas. The Honda CB750 Four came first, of course, in 1969, and created the pattern for all Honda Fours for the next 10 years. The air-cooled in-line four cylinder wet sump engine used a chain-driven single overhead camshaft and breathed through four carburetors. The engine was constructed in unit with the primary drive, wet clutch and five-speed transmission. An electric starter was standard, as was the disc front brake.

Honda’s mini-multis
Having effectively created the four-cylinder category, Honda took its bag of tricks and downsized them. Next came the 1971 Honda CB500 Four, then the 1972 CB350 Four. This last machine exemplified Honda’s flair for miniaturization but was not a technical success. With four heavy chrome pipes, mild tuning and meager power, it was slower than the company’s same-size twin and barely capable of highway speeds. It nevertheless lasted two seasons on the back of the four-cylinder fashion.

From an engineering standpoint, the 1975 CB400 Four was a simple evolution of the 350. An increase in bore size from 47mm to 51mm combined with the 50mm stroke gave 408cc, and while the engine cases were changed to accommodate a sixth gear, many engine internals including the crank, rods and camshaft remained the same. Honda did revise the cylinder head, however, increasing compression to 9.4:1. Even the four 20mm Keihin carbs were retained.

Styling was another matter entirely. Out went the mini-me 750 look; in came café sensibilities: rear-set foot controls, lower bars, voluptuous gas tank (with the new “Super Sport” logo) and a daringly asymmetric, in your face, four-into-one exhaust. The sweeping headers, like a chrome harmonica in front of the engine, instantly became the 400’s visual signature.

Similarly improved was the performance. Though Honda claimed just three extra horsepower (from 34 to 37 ponies) and only minor weight change, the standing-quarter-mile time went from the high 15s to low 14s, the extra cog no doubt helping as well. The baby Four could finally keep up on the freeway.

Serious sound
We’re all familiar now with the howl of a high-revving multi exhaling through a single pipe, but in 1975 this siren sound was new on the street. Honda’s previous multis and the Kawasaki 900 used four separate pipes. With the normal firing sequence of an inline four and given that the one-two and three-four pipes were usually paired, the result was a throbbing exhaust beat that sounded more like a twin. The CB400 Four created a new soundscape: At its 10,500rpm rev limit, the single pipe was blowing 350 beats per second, or roughly F above middle C. Contemporary reports concurred: the new sound was music to the ears of gearheads everywhere.

Though the CB400F sparked the café racer styling trend that would eventually give us today’s repli-racer sportbikes, it wasn’t universally appreciated at the time. Most professional testers (often part-time racers) noted that the bars were at an uncomfortable angle, but they liked the overall forward lean.

But the Average Joe of the day didn’t like any of it. Many dealers found themselves installing high bars to shift their inventories. And the abbreviated seat wouldn’t accommodate two regular-sized North Americans very well, so if you did meet that nicest person on your Honda, he or she might have preferred to walk. This is all familiar territory now, but Honda’s approach represented a revolution at the time, and like most pioneers, Honda suffered for it.

And it didn’t help that the CB400 Four wasn’t as fast as its competitors, most of which were two-strokes. Class leader was the Yamaha RD350 and RD400, while Suzuki’s and Kawasaki’s 400-class stroker triples would also walk all over the Honda. But the baby Four scored much better on handling, braking, reliability and general sophistication: An innovation on the introductory 1975 model, for example, was the now universal combined ignition/steering lock. And while the strokers have somewhat faded away, the little four gets more collectable all the time.

Don Hughes’ Hondas
When I drive up to Don’s house for our photo shoot, he’s unloading a crusty-looking Honda 750 Four from his trailer. It’s just one more tired motorcycle that will now get the Hughes treatment. Don presently owns 36 motorcycles, all of them Japanese. Of the 36, 18 are completed projects, while the rest are either in progress or waiting in the wings.

Read Don Hughes’ take on owning and riding a 1976 Honda CB400 Four

Don started restoring motorcycles 10 years ago after retiring as general manager of a printing company. His first projects were a series of Honda mopeds.

“When I retired, I decided I wanted to try something like this,” he says, “so I started on a little 1981 C70 Passport.”

The previous owner had dismantled the bike down to the last nut. “He even dismantled the starter,” says Don, and was using the frame to stop deer from running under his house! Fortunately, all the bits were in labeled bags that identified their origin. “I had it running in a couple of weeks,” says Don. “It was so much fun, I bought two more.”

Since then, Don estimates he’s restored more than 60 bikes, and his present collection includes a 1964 150cc C95 Benly, a hard to find CT200 dirt bike, an ST90 (the swivel handlebar model) and a 1964 50cc C115 Sports Cub. “I suppose you could say it’s become an obsession,” Don says.

Hondas are Don’s preferred brand because parts are more readily available. “The other makes, it’s very hard to find parts for the older bikes,” he says. “Every bike I do, I strip it right down to the frame, paint the frame and start checking everything as I put it back together. I don’t necessarily re-chrome everything or tear the motor to pieces unless I know there’s a problem with it.” The result is that Don’s bikes retain much of their period patina, giving them an authentic look that many over-restored bikes lose. Don’s minimalist restoration strategy ensures that many people will be able to enjoy seeing, hearing and riding these then-revolutionary machines just as they were. MC

Press reports
“If you can’t respond to the CB400F’s mechanical presence, you should immediately change your sport to checkers.”
Cycle, March 1975

“A shortish 54in wheelbase keeps the 400 in the compact category, the appropriate place for a sporting machine. This, however, puts the 400 pretty much out of bounds for behemoths, and relegates passenger carrying capabilities to the ‘occasional duty’ column.”
Cycle World, July 1976

“As revs rise, so does the exhaust note. To hear the 400F at 9,000rpm is to know why colorful journalists say racing machines wail. And it’s all legal.”
Cycle World, May 1977

“Honda’s original CB400F Super Sport made a rave-review hit with everyone here at Cycle, but it just didn’t play worth a hoot in Peoria. Oddly, and significantly, it was precisely those features we found most appealing that seem to have generated the greatest sales resistance.”
Cycle, June 1977

Read more about the motorcycles mentioned in this article:
Honda CB750 Four: A Classic for the Masses
Yamaha RD350

Honda CB400 Parts 
SOHC/4 Owners Club

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