Great Bikes of the 70's: Honda CB400F

The year 1975 saw the fall of Saigon, another ascent in oil prices, exoneration of the Kent State National Guard and the birth of disco.

Against such a backdrop of bummers, motorcyclists had one small reason to rejoice: one of the Japanese manufacturers finally got it right. That manufacturer was Honda, and the motorcycle in question was its exquisite, jewel-like CB400F.

The cafe craze--American homage paid to a distinctly European notion--was still in full bloom, and a small band of dedicated enthusiasts bought and fitted to their mounts uncomfortable-yet-racy clip-ons and rearset footpegs in hopes of emulating their brethren overseas, where there were no speed limits and everyone rode as hard as they could at all times.

Unlike now, when corporations employ legions of marketeers to identify and cash in on trends as they develop, some 20 years ago manufacturers responded to trends in somewhat the same way an elephant responds to a mosquito bite: A vague notion eventually registers that something is happening, and the response might be neither quick nor entirely appropriate.

With the 1975 CB400F, though, Honda nailed the bull's-eye. The 400 simply looked perfect, with just the right, understated amount of chrome, monochrome paint in blue or red, no stripes, foofraws or furbelows. That tapering, breadloaf-shape tank, the flat bar and slightly rearset pegs gave the requisite sporty riding position--and there sat that tiny four-cylinder engine, a totem for acolytes of Honda's Grand Prix excesses in the '60s. Here's what the magazines had to say about it:

"Obviously, we're dazzled by the first major manufacturer's 4-into-1 exhaust concept. It's light, maneuverable and quiet. This is the coming of a new kind of motorcycle--fast, silent and fun."--Motorcyclist, April 1975

"Honda has carefully tailored the 408 into a true mid-displacement sporting motorcycle."--Cycle World, July 1976

"The Honda CB400F is a marvel: It handles remarkably well, stops with authority, snaps through the gears precisely--and motors along smartly. The bike feels all of a piece, as if a hundred separate design systems fell into perfect synchronization. Yet the attraction of the 408 transcends its obvious competence. Even a card-carrying Anglophile would agree that the CB400F has real character. If you can't respond to the CB400F's electrifying mechanical presence, you should immediately switch your sport to checkers."--Cycle, March 1975

All this for a motorcycle that was essentially a restyled and hot-rodded CB350F. The CB350F had been an interesting technical exercise, but at more than 15.5 seconds through the quarter-mile, it was pathetically slow even then. Apart from the styling, pursuit of more speed became the focus of Honda's makeover. This was accomplished in straightforward fashion: A trip to the boring bar yielded a 51mm bore--4mm bigger than the 350F's 47mm dimension, for a displacement of 408cc. New pistons and combustion chambers brought the compression ratio up fractionally from 9.3:1 to 9.4:1. Bigger valves allowed more airflow. Honda also upgraded the clutch and added a sixth gear to the transmission, necessitating new cases. First and fifth remained the same, but second through fourth became slightly taller. Redline remained a giddy 10,000 rpm.

For the running gear, Honda changed precious little. A new fork with altered damper valving graced the front end, and a revised swingarm was fitted to the rear. Wheelbase remained the same as the 350F's--a short 53.3 inches. Most everything else remained 350F-spec: wheels, tire sizes, brakes and frame.

For its trouble, Honda got a motorcycle that could at least be mentioned in the same breath as the fiery two-strokes in the middleweight class. With quarter-mile times in the mid-14s, the 400F was almost a second quicker than the 350F, and slightly quicker than Suzuki's GT380 triple. But it was slightly slower than Kawasaki's KH400 triple, and almost a half-second slower than Yamaha's reigning RD350 twin. The RD and CB put out almost the same horsepower, but the RD was a telling 51 pounds lighter. In handling, the CB400F came up short against the RD's lighter weight, slightly better suspension and quicker turn-in. But the Honda offered--for the day--a stability that endeared it to many. From Cycle, March 1975: "The 408 inspires confidence by providing a stable platform for carving down a winding road."

Unfortunately, the buying public was not as smitten with the CB400F as were the enthusiast press. Part of the problem was the sporty riding position so loved by the magazines and cafe cultists. Riders less interested in grinding off the metal balls on the ends of the pegs hated the 400F's ergonomics, and either fitted a higher handlebar, or simply stayed away altogether.

Honda sold a fair number of the 400Fs (see "400 Fours for Sale"), but by the time the company got around to fitting a higher bar and more-forward-mounted pegs for the '77 model, it was too late, and next year the 400F was gone. It didn't help that Honda was making little to no money on the little four. According to Jerry Wood of J. Wood and Co. Auctioneers, "The reason Honda discontinued it is they did a cost analysis and found out they were selling it for a loss. It actually cost them almost as much to produce the CB400 as it did the CB750."

While the little 400s couldn't find that many homes with street riders, more than a few found their calling on the racetrack--especially those fettled by Kaz Yoshima. An alumnus of Honda Japan's R&D; department, Yoshima had opened his own shop (now Ontario Moto-Tech) in 1975, and decided to focus his attention on the CB400F as a means of self-promotion. "Originally I heard that engine doesn't have potential--a well-known four-stroke guy said that," Yoshima remembers. "So it gave me a bit more extra challenge. It was a difficult motorcycle, though, to keep together."

Problem was, Yoshima was having to spin the crank way past its stock 10,000-rpm redline, and the rods and plain bearings would have none of it. "I really wanted to spin 12-5 to 13-5, to compete against 1000cc-class bike. But oil pump wasn't sufficient, bearing wasn't sufficient, rod wasn't sufficient, so everything comes apart." In other words, rods broke and tried to make an escape through the cases; the engine would grow legs.

Yoshima eventually used Carrillo rods and a GL1000 oil-pump rotor to make the engine survive. Thusly equipped, and with his 492cc pistons, cam, pipe and some select HRC pieces, the little CB was a 135-mph-plus giant-killer. One of Yoshima's customers, Steve Schrader, won five club championships and 38 races on such a bike from 1977 to 1980. Several Motorcyclist staffers past and present also rode Yoshima's test mule. Last Page Editor Jeff Karr had this to say: "It was pretty darned fun, 'cause [Kaz's bike] was pretty tweaked. The thing was really fast, and torquey too; it really ran strong. It made a pretty formidable racebike. I remember it being an easy bike to ride."

Senior Editor Art Friedman: "It was a little quicker than a Z-1. Nice power characteristics as well as a lot of it. It handled great by the standards of the period."

Before the mists of fond remembrances blind us completely, though, let us point out that Yoshima's bike had modified suspension, strategic frame-bracing, wider rims and thicker-gauge spokes. Stock, the bike was a good handler on the street--for its day.

Riders weaned on modern machinery would be horrified by the CB400F's rather narrow performance envelope. Not to put too fine a point on it, the CB400F's riding position is roughly akin to being stuffed fanny-first into a 55-gallon drum; the steering geometry, short wheelbase, 18-inch-diameter wheels and high CG yield steering that's at once quick and clumsy at speed; the suspension rarely responds to bumps in any useful manner; the hydraulic disc front brake rewards high effort with little stopping power; and the engine revs to its 10,000-rpm redline with agonizing slowness. "It felt like a museum exhibition in internal friction," Karr says. Ex-Motorcyclist staffer Ken Vreeke rode a stocker at Willow Springs in 1989, and wrote this for Cycle: "Hard braking while turning had the fork twisting, the frame flexing as if hinged in the middle, and the whole bike hopping violently enough to chirp the tires."

As with most any period piece, Honda's 20-year-old CB400F best rewards more casual efforts. Rides are best spent appreciating the work that went into creating the intricate little four-cylinder, unique in its day, the mum-hum of its exhaust, and its significance in the motorcycling firmament.

It goes something like this: The CB400F was a bold move for Honda, but not a particularly risky one. It marked the first time that a Japanese motorcycle manufacturer successfully captured the Euro-sporting look, but cosmetics are relatively inexpensive to produce, and the majority of the bike's hardware came from the defunct CB350F. Honda chose the middleweight class to debut the look, too, not the higher-profile 750 or open classes; the market for a rather expensive 400cc multi would be naturally small, so if the experiment failed, little would be risked. And while the CB400F's performance could keep it afloat in a class awash with speedy two-strokes, the price--$150 to $250 more than the class cacklers--was too dear. As for the Euro look? Not another Japanese manufacturer would try to duplicate it until Honda tried again with the GB500 in 1989, and it suffered the same rapid demise.

Some 20 years after the CB400F first hit these shores, gas prices have skyrocketed again and disco is making a comeback. And the CB400F might at long last find its audience. Some of us knew it was there all along.

Honda CB400F: Charting the Changes
Three strikes, you're out

Honda's mini multi came and went about as quickly--and about as successfully--as Comet Kohoutek had just a few years earlier. Relative unpopularity, before the era of sweeping year-to-year changes, ensured the 400F would be gone at the end of three years with few changes.

Even American Honda doesn't have many details about changes to the 400F, so we're left with mentioning what we can actually see, and some references from period road tests.

For the 400F's second year, in 1976, Honda changed only four items. New rear shocks gave increased rebound damping. (Honda microfiches show that the 1976 shocks do carry a different part number from the 1975 items, but visually they're identical; they're also the same shocks used on the 1976 CB500T and CB550F.) Secondly, a shorter reserve fuel-feed tube in the petcock drained more of the gas. Third, Honda changed the color, deleting the Varnish Blue hue and adding Parakeet Yellow to the existing Light Ruby Red. Fourth, the plastic side covers changed from tank-color to black.

Sagging sales convinced Honda to nudge the '77 bike a bit closer to the expectations of mainstream American riders. That meant a higher handlebar with more pullback, more-forward-mounted footpegs for a less-sporting riding position, and a little more pizazz in the form of accent stripes applied to the gas tank. The tank also got a recessed cap with a fumbly filler door in place of the previous models' classy chrome pop-top. Blame the lawyers; apparently some 1975 models' caps popped open in crashes, and Honda sent out locking devices to owners the following year. The 1977 arrangement dealt with the matter, however, none too elegantly.

It was all too little too late, though. After three years, the littlest four struck out. --C. E.

A lone disc up front gave the little 400 plenty of period braking power. (Some miscreant also seems to have slipped the '77-model's higher handlebar onto our photo bike.)
This candy red, first-year ('75) 400F appears to be nice and original apart from the ugly "crash bars"bolted to the engine cases. The F's sexy 4-into-1 exhaust system was an object of wonder in '75--and still is.
Apparently minted directly from Honda Japan's skunk works race shop, the little 408cc, SOHC four revved to 10,000 rpm.
Our own Senior Editor Art Friedman (among others) piloted Kaz Yoshima-built 400F endurance bikes on numerous giant slayings. Spinning toward a semi-reliable 12,000 rpm, Kaz's bikes had the juice to outrun 900s on a good day.