The Honda CB450 Black Bomber

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The Honda CB450 Black Bomber.
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The Honda CB450 Black Bomber.
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The Honda CB450 Black Bomber.
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Doubtless most Honda owners never had to use the provided tool kit on the Honda CB450 Black Bomber.
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The red taillight was about the only spot of color on the early Honda CB450, which came only in black with silver.
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Number plate was added for fun on the Honda CB450 Black Bomber; this is no race bike.
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The Honda CB450 Black Bomber.
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The calling card on the Honda CB450 Black Bomber was its double-overhead camshafts, a feature then found only on exotic race bikes, and certainly not on “cheap” Japanese street machines.
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The Honda CB450 Black Bomber.
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The Honda CB450 Black Bomber.

Honda CB450 Black Bomber
Years produced:
Claimed power: 43hp @ 8,500rpm
Top speed: 102mph (period test)
Engine type: 444cc DOHC air-cooled parallel twin
Weight (wet): 430lb (195kg)
Price then: $1,000 (approx.)
Price now: $3,500-$6,000
MPG: 40-45 (est.)

“All warfare is based on deception. Therefore, when capable, feign incapacity; when active, inactivity. Pretend inferiority and encourage his arrogance.” —­­ Sun Tzu, “The Art of War”

Widely recognized as one of the most important motorcycles ever launched by Honda, the Honda CB450 Black Bomber is celebrated as the company’s first “big twin” and as the first volume production double-overhead cam. Lauded and hyped by motorcycle and car magazines as one of the most remarkable machines ever, it was in fact a slow seller, never quite lighting the market on fire as Honda might have hoped. To understand the impact the CB450 had, it’s important to understand the U.S. market of the early 1960s and what led Honda to introduce the 450.

In the beginning …

Honda started exporting motorcycles to the United States in 1959. At the time, Honda was the largest motorcycle manufacturer in the world, selling 500,000 small motorcycles a year, mostly to Asian countries. Honda wanted to sell even more motorcycles, and astutely recognized that the U.S. market, where motorcycle registrations totaled a modest 500,000 or so, had great untapped potential.

Americans were buying some 60,000 motorcycles a year, about 12,000 of which were Harley-Davidsons. A large percentage of the rest came from England. Harley-Davidson was running on a tight budget and had little money for advertising, and the British companies were basically content with the market as it was; efforts to increase the numbers of riders were hamstrung by the refusal of English management to spend money on improving the product or on aggressive sales efforts.

By contrast, Honda was designing bikes to meet the specific needs of the American market. Teenage baby boomers were interested in speed and offroad competition, and so the 1961 product lineup featured the 305cc Super Hawk, a peppy little overhead cam twin, and the CL72 Scrambler, a 250cc OHC twin with a smaller tank and high pipes.

American Honda embarked on a marketing effort that, like a successful military campaign, was well funded and carefully thought out. Targeting non-riders, Honda placed ads in general interest publications marketing its bikes as a means of fun, carefree recreation. Honda was introducing motorcycles to a new leisure market, and great effort was made to promote a squeaky clean image through its “You Meet the Nicest People on a Honda” campaign. It worked. In 1962, only three years after renting a storefront on West Pico Boulevard in Los Angeles, U.S. Honda motorcycle sales were up to 65,000 units. A year later, sales reached 150,000. By itself, Honda had more than doubled total U.S. motorcycle sales.

The market grows

Paradoxically, Honda’s effective advertising expanded the market for all motorcycle manufacturers. Harley’s sales went from under 10,000 in 1963 to over 25,000 in 1965. In New Jersey, Berliner imported increasing numbers of BMWs and Ducati singles, and the British importers found themselves selling as many bikes as the home factory could pump out.

At first, British motorcycle companies did not see Honda as a direct threat. Triumph’s Edward Turner had convinced himself the Japanese were a long way from building the large sporting twins that were the backbone of British sales in the U.S., and he convinced his American distributors he was right. Heeding the words of Sun Tzu, Honda was careful to do nothing to alarm its competitors, while building up its retail base in the United States.

In 1964, a visiting journalist discovered Honda testing a 450cc twin at its factory track at Suzuka, Japan. The discovery shocked the British manufacturers, the standard-bearers of the traditional vertical twin. On sale a year later in both Europe and the United States, the new twin demonstrated Honda’s technical capacity. Honda had invested heavily in a state of the art foundry and the best tooling obtainable, and as a result could economically build designs that were out of reach for manufacturers with more antiquated equipment.

Full attack

Nicknamed the Black Bomber (like the Model T, the CB450 was available in any color you liked — as long as it was black) the new CB450K0 twin had double-overhead camshafts at a time when the only motorcycles so equipped were purpose-built racers. In fact, the Bomber was disqualified from some production races in England on the grounds that it was too much like a factory racer.

The 444cc twin was a running portfolio of Honda’s emerging capacity. Four caged roller bearings supported the crankshaft, and primary drive was by spur gears. The valves were seated by torsion bar valve springs — short lengths of steel splined into tubular guides. Tight valve clearances and effective mufflers aided quiet running. The 450 also boasted a pair of 36mm constant velocity carburetors, a first on a production motorcycle.

Honda claimed the short stroke engine would develop 43 horsepower at the crankshaft and could reach 112mph. Cycle World recorded a top speed of 102mph in its August 1965 review. In contrast with most other bikes of the time, which pulled strongest at lower rpms, Honda’s 450 produced its best power over 6,000rpm. Reliability was excellent, provided you remembered to warm up the engine and changed the oil regularly — the service manual suggested 1,500-mile intervals. The horizontally split cases didn’t leak, and the electric starter always worked, hot or cold.

Contemporary testers noted several faults, including poor rear shocks, vibration and the aforementioned need for a longish warm up to ensure a sufficient supply of oil to the top end. Over-revving the bike when cold could cause premature engine failure. Some also noted the bike’s oddly spaced gear ratios and the lack of a 5-speed transmission, a feature that would finally come a few years later. And at a dry weight of 412 pounds, the K0 was heavier than a contemporary Triumph 650, which weighed in around 365 pounds dry.

The Bomber was moderately successful, but Honda belatedly realized it would be even more successful if the styling, with its somewhat odd, humpbacked gas tank, was more mainstream. In February 1968, the K0 was superseded by the K1, with a 5-speed gearbox, a more conventionally shaped tank, a larger oil pump to aid warm up and a longer wheelbase to improve handling. After the introduction of the CB750 Four in late 1968, the 450 twin was no longer Honda’s flagship, but continued through 1974 in an important role as a middleweight street machine. Honda reintroduced the concept with the 395cc Hawk in 1978, one of the most reliable commuters ever built.

Early Japanese motorcycles become classics

Early classic motorcycle enthusiasts were interested in the pioneer bikes built before World War I. As the vintage movement matured, a wide variety of older motorcycles — including 1960s Japanese bikes like the Bomber — became accepted as classics. “As the Baby Boomers return to the enjoyment of their youth, there has arisen an emerging market for older Japanese motorcycles,” notes Roger Craig, who is the prior owner and restorer of our test bike. Increased interest in bikes made in Japan in the Fifties and Sixties led to the formation of the Classic Japanese Motorcycle Club (primarily West Coast) and the Vintage Japanese Motorcycle Club (organized in 1977 and stronger on the East Coast) both of which organize rides, shows and swap meets. Roger is a member of both.

Roger grew up in Melbourne, Australia, a hotbed of motorcycle enthusiasm, and as a teenager was an enthusiastic rider of small Japanese bikes. He eventually moved to the U.S., got married, raised a family and got involved in other things. “Many years later,” he explains, “I had an opportunity to return to motorcycling. I had more free time, and I wanted to go back to something I enjoyed.”

Roger found himself drawn to restoring and collecting the Japanese classics. “I first got a Kawasaki W650 — one of the new classic-appearing bikes,” he says. “Later, I found a 1976 Honda 750, a real classic. I did a few restorations, and I settled on the idea of a Bomber. When my wife, Ann, and I were at a motorcycle show, she was really taken with one that was there — the appearance, the proportions.”

Roger then went out on a search mission. Bike broker Allan Siekman had a frame for him, but even with eBay, locating parts was challenging. Although many of the engine parts are easily available, sheet metal, especially one-year-only parts like the front suspension, tank and seat, are hard to find. “I tapped into the old Japanese bike network,” Roger remembers. “I found David Silver Spares in the U.K., one of the best sources for pre-1970 parts. This is where belonging to a club and being part of the network comes in. People are willing to help one another.

“People who need a part will often make more than one. For example, a gentleman in South Carolina had extra seat hinges manufactured during his own Bomber restoration. Greg Clauss, of Clauss Studios, is a friend who makes parts in rubber and plastic. People call me for help locating parts. Someone called me just the other night, and I did what I could.”

He continues: “The key to completing a restoration is understanding the sequence of events. Things come together in a certain order. You also have to know your strengths and limitations. I try to avoid engine rebuilding, so I look for an engine in good condition. With the Bomber, that was not possible, so I had Charlie at Charlie’s Place in San Francisco do the rebuild on this bike engine.”

Roger explains that one of the key decisions to be made early on in the restoration is whether the bike is to be a rider or a show bike. “What you aim at is what you will end up with,” he says. “For me, the bike was restored and built to ride. I bought new tires and updated the electronics. The charging system was not reliable on bikes of the era.” Roger approaches a restoration in a methodical way: “I work on one project at a time. Some people may think I am anal retentive. I think of the process as ‘Classic Project Management.’ I make a commitment to do something every day. For me, that works.”

The Bomber moves on

Roger was not planning on selling the Bomber. He was enjoying having it around. “Even today,” he says, “the rideability and durability of the Bomber, its acceleration and cruising speed, and its ability to stop make it continue to be used.” He believes that the handling complaints of contemporary testers were overstated — or perhaps simply due to bad tires and too-light fork oil. “It’s a good bike for someone who wants to enjoy a ride — even a spirited ride,” he explains.

Word got out that Roger had this really nice Bomber, and a broker approached him with an offer. He wavered a bit, but decided to part with the Bomber after learning it was to go to a museum. “We are simply custodians of these machines,” Roger says. “It’s good that it’s going somewhere where others will see it.”

Collector Guy Webster has always liked Black Bombers. Best known for his Italian motorcycle collection, Guy has recently started picking up early Japanese machinery for his museum. “I had a Bomber in 1968 and loved it,” he says. “There’s a place in my heart for Fifties and Sixties Hondas — but only those years. The 4-cylinder 750s were works of mechanical art.”

Guy only recently took delivery of this bike, but has already taken it out for a ride. “This is a rider for me. The bars are not correct, but they are better for me than the stock ones,” he says.

The 5-speed box is actually correct. Honda made an unbelievable variety of racing parts, and the 5-speed box was one of the parts you could get.

“It has guts — I like the twin cam. The sound is spirited, and I like just listening to the Bomber idle. The shocks don’t bother me if I’m not racing. It handles just fine. I used the wide apex method of getting through a turn, and it held its line perfectly. I tried hanging a knee out, but there was no difference. The brakes are superb — I am thrilled with the brakes. They aren’t grabby, and there is a good feel. Drum brakes work if you set them up properly, and Roger did an excellent job.” The one thing Guy doesn’t like is the neutral light: “It’s the size of a pin, and hard to see.”

The date the Bomber went on sale is a dividing line in motorcycle history. Before that date, Japanese motorcycle manufacturers weren’t taken seriously in the world market. After that date, they were. The Bomber showed its competitors that Honda could not only match what other manufacturers were doing, it could go far beyond them in technological development.

“Attack where he is unprepared; sally out when he does not expect you.” — Sun Tzu, “The Art of War” MC

Press Reports

“The CB450 is blessed with one of the better seating positions in the world.”
Cycle World, September 1965

“Featuring the world’s only production-line DOHC motorcycle engine, this largest of the Hondas makes up with performance and combustion efficiency what it pays for in weight.”
Cycle, November 1965


• Clymer’s “On the Lift” test:

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