1975 Honda CB400F: The First Real Sportbike

Honda’s CB400F only lasted three years. But as Japan Inc.’s first real sportbike, it heralded the rise of a powerful category.

1975 Honda CB400F
This photo is not from the archives! Charlie's Place in Glendale, CA (charlies-place.com) restored this 400F for owner Jim Larriva of Alhambra, CA.©Motorcyclist

Most of the market trends and technical innovations in our amazing sport have some interesting historical roots. Take production-spec inline-four engines and disc brakes, for instance. Where did they first appear? On Honda's mighty CB750, of course. How about the Japanese-built custom? Kawasaki's 1977 KZ900 LTD gets the nod. Or monoshock-equipped motocrossers? Yamaha's mid-'70s YZs had it first.

But how about the bedrock material upon which the Universal Japanese Sportbike is comprised: sporty, low handlebars, rear-set footpegs, and a lightweight, racing-style exhaust? The 750 Four didn’t have the goods, nor did Kawasaki’s shrieking H1s and H2s, or even the magnificent ’73 Z1. Yamaha RDs, so amazingly popular in the 1970s, came with high bars and silly, forward-mount pegs that threatened to toss you off if they grounded.

Throwback: 1975 Honda CB400F
Throwback: Sportbikes and weight-saving engineering weren't common in the '70s, which made Honda's high-revving 400F—with lightweight 4-into-1 exhaust—a bit of an anomaly.©Motorcyclist

Nope, none of them is the one. But if you look back and identify the very first production Japanese motorcycle with the hardware and aesthetics of a truly modern sporting machine, the bike that led more or less directly to the 16-valve CB-Fs, VFs, VFRs, and CBRs (as well as to GSX-Rs, Ninjas, and YZFs), Honda’s 1975 CB400F Super Sport is that bike.

That’s not to take away from the CB550F and CB750F Super Sports, which debuted that same year and made Honda a somewhat surprising player in the then-new proddie café racer/sportbike category. They, too, had some of the 400F’s sport-biased engineering and aesthetics. But it was the sleek, purposeful, lithe, and downright sexy 400 Four that best exemplified Japan’s move toward Euro-inspired sporting machines, bikes like Ducati’s 750SS and BMW’s R90S.

Jim Larriva's restored CB400F
Jim Larriva of Alhambra, CA, lent us his beautiful 400F for photos. Charlie's Place in Glendale, CA, recently restored it with a period-correct aftermarket Yoshimura exhaust.©Motorcyclist

Like the 550F and 750F, the CB400F was built upon the carcass of an existing product—in this case the technically interesting but thoroughly unexciting CB350 Four. Cycle magazine described the 350F as “a reply to a query never raised—unless one wanted to know how few cubic centimeters Honda could split by four.” Charming, sophisticated, and polished the CB350 Four may have been. Exciting it was not.

To boost the 350F’s performance and persona to attain what designers were after with Honda’s new sporting middleweight, the R&D team went to work in late 1973 on the 350F’s engine and chassis. As an answer to a question no one had asked, the 350F didn’t sell particularly well and didn’t fire the imaginations of a great many enthusiasts. But its engine—an air-cooled, 347cc four with a then-unreal redline of 10,000 rpm—was a marvel of compact engineering and provided engineers a fine place to start.

Archive photo of Honda CB400F
Honda’s exhaust was stunning back in the day. Even at rest, the 400F had a sporty appearance.©Motorcyclist

With the 350F making less than 30 hp, the primary goal for the 400F was power production—and the more the better, especially with the rapid Yamaha RD350 to compete against. Out came the boring bar, and a bore increase of 4mm, from the 350F’s 47mm to the 400F’s 51mm, which yielded a total displacement of 408cc—which explains the bike’s “408” nickname after its launch. The larger bores necessitated a redesigned cylinder head and new pistons, and while engineers were there, they also added slightly larger valves for increased breathing capacity while keeping the 350s mild cam to move them. Compression from the new pistons and combustion chambers went up fractionally, from 9.3 to 9.4:1.

Carburetion remained status quo, 20mm Keihins, though the 350F’s heavy 4-into-4 exhaust was binned in favor of what would become largely de rigueur in the coming decades for sporting motorcycles: a 4-into-1 exhaust. And a beautiful thing it was, too, the four chrome pipes exiting the jewel-like cylinder bank and swooping dramatically to the right, finally gathering at a lovely, angled collector just below the right peg. Aft came a beautifully tapered megaphone, which looked just right. If any one component defined the 400 Four, it was that exhaust.

Restored CB400F with 83 miles
The odometer on Jim's bike showed just 83 miles when we picked it up. We added a few more during our shoot.©Motorcyclist

Belowdecks, Honda added a sixth gear—which necessitated new crankcases—and a sturdier clutch to handle the added power. Redline remained a giddy 10,000 rpm, though post-release testing showed it could be revved safely to 10,500.

Chassis-wise, changes were limited to a revised fork with uprated damping and a new swingarm assembly that, curiously, had passenger pegs attached. One imagines this was done as an afterthought, as passengers were certainly way down the bike’s priority list. (Or maybe, as cynics have jokingly suggested, the design was meant to buttress the rear suspension.) The steel-tube frame was basically a 350-spec piece, which held the wheelbase at 53.3 inches, 4 inches shorter than a CB750’s. (Even Honda’s current CB500F twin, not exactly a large bike, has a 55.5-inch wheelbase.) This was definitely not a tourer.

CB400F front wheel
Honda revised the 400F fork with uprated damping. Jim's bike was lowered slightly during the restoration to suit his stature.©Motorcyclist

The tank, seat, and side panels were all new and together gave the 400F a serious and sexy look, especially with the bike’s stunning blue or red paintwork options. Luckily, stylists eschewed chrome badges and foofaraws on the panels and tank, staying with decals. Of course, a good portion of the 400F’s aggressive, purposeful look came from its narrow and low handlebar and sporty, rear-set pegs. Even at rest the 400F had a sporty appearance, and just staring at the thing made back-road fans woozy with lust.

The 400F debuted in late ’74 in Cologne, Germany, to big-time excitement, with European enthusiasts and journalists alike loving both the idea and the execution. Production began in December of ’74, with availability scheduled for Europe, Japan, and North America. American Honda signed up for a load of the things, some 38,000 units in 1975 alone, which indicated how confident Honda Japan and its US importer were that it would be a success.

That excitement was palpable early on in the US, both from an enthused press corps and a particular segment of the riding public starving for something sportier than the café racer customs they’d been building to satiate their twisty-road intentions. The question was, just how many of these customers were out there? Honda, by importing so many 400Fs, and also offering the 550F and 750F, was betting there were enough.

1975 Honda CB400F seat
No hipster café racer mods here!©Motorcyclist

For the most part, the US press wrote glowingly about the 400F. Negatives were limited to a few items: not enough rearward bend in the handlebar. Unsophisticated suspension. A slight lack of cornering clearance (with heavier riders) on the right side. Some minor cold-bloodedness. The swingarm-mounted passenger pegs. A bit of driveline lash. And not as much power as the dominant Yamaha RD. Otherwise, editors loved it.

“Put bluntly,” Cycle wrote, “[the CB400F is] really fun. In this case, Honda’s lustrous detailing does not brighten up a pale, lifeless motorcycle. The CB400F is a marvel: it handled remarkably well, has sufficient cornering clearance, stops with authority, snaps through corners precisely—and motors along smartly. The bike feels all of a piece, as if a hundred separate design systems fell into perfect synchronization. The CB400F has character.”

CB400F frame
The steel-tube frame was basically a 350-spec piece, which held the wheelbase at 53.3 inches, 4 inches shorter than a CB750’s.©Motorcyclist

“It’s light, maneuverable and silent,” wrote Motorcyclist Editor Dave Ekins for our April ’75 issue. “It’s so quiet all you hear is the gentle whine of the gears—inlet and exhaust noise is almost non-existent. This is the coming of a new kind of motorcycle, fast, silent, and fun.”

Unfortunately for Honda, consumers were less enamored, especially those in middle America, where the café racer/sportbike thing hadn’t yet penetrated the riding public’s consciousness. In Peoria the bike’s riding position was deemed cramped, and because passengers and touring fairings didn’t really mesh with the bike’s MO, many potential buyers passed.

1975 Honda CB400F headlight
A serious and sexy look in 1975.©Motorcyclist

More damning was the performance gap. Although the 400F was a full second quicker in the quarter mile than the lethargic CB350F, it was nearly a second slower than the hot-rod RD350 Yamaha, which was also more than 50 pounds lighter—and a racetrack weapon right out of the box. Kawasaki’s 400cc S3 two-stroke triple was also faster point to point, and the fact that the 400F was a bit quicker than Suzuki’s chubby GT380 did nothing to balance the performance scales. On top of it all, the 400F was a couple hundred dollars more than its direct competition, and with engine performance and weight already going against it, it was often a hard sell.

CB400F seat
Tool kit, registration papers and air cleaner access under the seat.©Motorcyclist

“I sold CB400Fs and RD350s and 400s side by side for a few years,” remembers Jack Seaver, who worked at two dealerships in the Washington, DC, area in the mid-1970s. “The CB400F was a beautiful and superbly pieced-together machine, the Swiss watch of motorcycling, really. It took your breath away to look at it, and it functioned really well. But the people who gravitated toward the café racer-styled bikes were performance-minded, and all any of them had to do was read the magazines or go watch a club race at Summit Point to know that the RD350 would blow a CB400F into the weeds. And it only got worse when the faster and sleeker RD400 came out in ’76. By then, the CB400F was finished. Honda had the look, but Yamaha had the goods. And everyone knew it.”

“The 400 Four was a fantastic motorcycle,” remembers Bob Troxel, who worked at a Honda/Kawasaki shop in Wichita, Kansas, from the early ’70s on, finally buying place in the early 1990s. “I love the things and have owned a handful. But sadly, it was a bike ahead of its time—a bit too expensive, heavy, and slow, and a bit too early for the sportbike wave, which came later. Still, there are few motorcycles as aesthetically right as the CB400F.”

Aesthetics and sex appeal, of course, weren’t enough, and in the end, the 400 Four only lasted three years, ’75 to ’77. The bike appeared in limited numbers (just 6,200) for our bicentennial year, again in red and also in a stunningly beautiful Parakeet Yellow, and then again in ’77 (just 4,200 were imported) with a higher bar, conventional footpegs, and some tank striping. This was not a successful strategy on Honda’s part: Enthusiasts pooh-poohed the ’77 model, while Peoria still wasn’t convinced to buy. A year later it was gone, the victim of average sales, not enough power for its class, and, probably more importantly, a fact no one outside Honda knew until years later: Because of the 400F’s ultra-high build quality, attention to detail, and four cylinders (and four carbs, and pistons, and rods, etc.), it cost as much to produce as the company’s CB750. And at a retail price of $1,433, Honda was, at best, breaking even.

CB400F legacy
The 400F’s legacy is plenty rich despite its quick demise.©Motorcyclist

The irony here is huge; the very parts and technology that made the 400 Four such an emotionally riveting and functionally excellent motorcycle helped doom it in the marketplace. Of course, the 400F’s legacy is plenty rich despite its quick demise. For one thing, it’s become a genuine classic over the years, delivering untold amounts of ownership, restoration, and riding satisfaction to thousands of enthusiasts around the globe.

But more importantly, it’s what the 400F helped engender that’s key. By arguing the case for the purposeful, sporting motorcycle with a low bar and rearsets so firmly and successfully way back in ’75, before the bulk of baby boomers (the leading edge of which turned 30 that year) could get their heads around the concept, the 400F had an arguable and heavy hand in kickstarting a trend that would explode during the 1980s—and continue to this very day.