The Honda CB750 Four: Classic for the Masses

Editor-in-Chief Richard Backus and I had the chance to drive out to north-central Kansas not long ago to visit Dale and his 750. As the proud owner of a 1976 CB750 K6 I’ve been working on for just over a year, it was a trip I’d been looking forward to.

As we walked around Dale’s bike, ogling the perfect condition of pieces such as the emblems, gauges, exhaust system and more, answers to questions of origin started to have a broken-record effect. What isn’t original on the bike (albeit meticulously cleaned and polished) is NOS — new old stock. These are factory made replacement parts, most of which are identical to the original ones they replace. And while it isn’t a miracle to find NOS parts for some machines, the market has been picked very clean for early Honda CB750 pieces in recent years, as the value of these beauties has risen.

But that wasn’t the case back when Keesecker and his mechanic restored their K0 beauty; Keesecker and his CB were ahead of the curve. It’s not an uncommon story. These 750s were ahead of the curve before they ever hit showroom floors.

Though Honda is a well-known and well-respected manufacturer of motorcycles, automobiles and more today, that wasn’t the case in the mid-1950s. In fact, it wasn’t until 1959 that Honda decided to expand into the United States. And though they were already the largest motorcycle manufacturer in the world at the time, selling hundreds of thousands of lightweight motorcycles around the globe, there were obstacles that would have to be overcome to make expanding into the U.S. profitable.

The first challenge was changing the bad image many people in America held of motorcycling. The second was changing the low opinion of the quality of Japanese products held by many Americans. Both images were changed with a little persistence, a lot of public relations and lots of advertising. The fact that Honda made good, dependable, practical machines was another obvious key. By 1963, Honda had exported 150,000 motorcycles into the states.

But as much as Americans loved the little Japanese bikes they were buying and riding all over the U.S., they wanted more. More displacement. More power. More features. By 1965, Honda’s engineers had cooked up the 444cc double overhead cam Honda CB450, which featured large drum brakes, electric start, and a four-speed transmission. It was closer to what the American rider was looking for, but they still wanted more.

The Tokyo Show in October of 1968 was where the world finally got to see Honda’s response to its customers’ desires. Although some motorcycle industry pundits had figured Honda’s new offering of the day would be a twin, it turned out to be a transverse, in-line, 736cc single overhead cam four cylinder, and one that beared more than skin-deep resemblance to the factory’s 500cc GP competition motorcycle. The company went for a SOHC design to make the engine more compact, and the central location of the single camshaft made it possible to design low-profile cam covers, which aided the engine’s location in the frame. It was one of the first production road machines with a transverse, in-line four-cylinder setup.

Another surprise ingredient Honda threw into the mix was the first hydraulic, single-disc front brake on a production motorcycle. At the time of the CB750 premiere in the January 1969 issue of Cycle World, the magazine had only tested two other bikes that featured similar hydraulically operated brakes; a Dunstall 750 and a Rickman Triumph Metisse, and they lauded praise on the design. “In each case,” they said, “the unit proved markedly superior to the cable-operated drum brakes and [were] far smoother in operation. Presumably, the Honda version will offer similar benefits.” Later tests proved the merits of the new system, which, for its day, offered a surprising amount of stopping power with good feel.

But aside from the single cam and single front disc brake, it seemed as though the blessings came in fours – as in four cylinders, four carburetors and four racing-style megaphone exhaust pipes.

The CB750 became an immediate success as soon as it went on sale. Although the bike had its critics (who mostly focused on its unusually high weight for the time and the handling changes that went with weight), testers and customers alike raved over the electric start, oil-tight reliability, great brakes and the power and cruising ability the big engine provided.

Through the Years

Though there were a variety of small changes made over time, most were small. First-year color choices included Candy Blue-Green, Candy Gold or Candy Ruby Red. The first CB750’s had engine cases with a wrinkly finish, a result of the sand castings used to make the alloy engine cases. Partway through the run of CB750 motorcycles, a switch was made from sandcast cases to cases formed with more traditional methods. The reason for the switch was the brittleness of the sandcast cases. Very powerful for its day, the first CB750 was harder on the drive chains than many bikes before it, and without proper maintenance, the chains would break. When they did, they often flew forward and broke parts of the engine case, forcing owners to replace them with the new cases of later design. This is one of the many reasons a true, original sandcast CB750 K0 is fairly rare. There are also a variety of very minute changes within the production K0 models, including the mounting of the horn switch from the left side of the handlebar to the right somewhere within the production run. Roughly 7,414 sandcast CB750s were manufactured.

The run of the CB750 K0 continued until September 21, 1970, when the CB750 K1 was introduced. The K1 wore smaller side covers that were missing the cosmetic slots seen on the K0. The lone mechanical change was the implementation of a two-cable throttle system in place of the 4-into-4 design used on the K0. The new design worked by having one cable pull the throttles open while the other pulled them closed.

It wasn’t until March of 1972 that the CB750 K2 was released, and changes were few. Until this point, the headlight housing had matched the paint color, but for 1972 it came in black only. The fork leg uppers also changed from being color-keyed to chrome. Paint choices were Candy Gold, Brier Brown Metallic and Flake Sunrise Orange. A different taillight was used, along with larger side reflectors on the front forks.

For 1973, the CB750 K3 version was introduced. The fuel tank striping was now black with white and gold accents. Paint options consisted of Flake Sunrise Orange, Candy Buchhus Olive, and Maxim Brown Metallic. These were the only changes made to the K3. The 1974 K4 model brought wider white stripes on the fuel tank graphics. Sunrise Orange was available again, and it was joined by Freedom Green Metallic and Boss Maroon Metallic. The 1975 K5 sported darker green instrument faces, and the speedometer now read in increments of 10 instead of 20. Planet Blue Metallic and Flake Apricot Red were the paint color choices. The 1976 K6 featured lighter green faces on the instruments, and was available only in Candy Antares Red.

While the CB750 continued on for 1977 and 1978 without major mechanical changes, the appearance of the bike changed just enough that while the lineage is obvious, these models don’t command the same prices or desirability of the K0 through K6 models. Major changes included a more slab-sided fuel tank and side covers, along with the lack of heat shields on the exhaust pipes and the addition of a stepped seat. A new dual overhead cam, 16-valve 749cc engine was introduced for 1979, and it powered the 1979 CB750 K, officially bringing an end to the 10-year run of SOHC CB750s.

More than 35 years after its debut, the original CB750 has been eclipsed in terms of performance, but it’s still adored by riders around the globe for its accessibility, usability, reliability and the fact that despite all the other choices out there for motorcyclists today, the bike is still classically cool. As I said, the more things change …. MC

Read more about the other motorcycles mentioned in this article:
• Dale Keesecker’s Vincent Specials
• Honda CB450: The Black Bomber