Three Shades of Honda

50th Anniversary Tribute

Introduced in Tokyo late 1968, the landmark CB750 Four benefitted from extraordinary timing. Being the hot ticket in movies and television, Hollywood capitalized on the outlaw biker stereotype all through the 50s and beyond, and that kept some buyers away. Honda, maker of step-through 90s and camping generators rewrote the rules by promoting motorcycles as wholesome family fun. Being nice was admirable in 1969, and from a US rider’s perspective Honda’s hot 750 delivered whopping doses of street cred for a fraction of the cost of a new Corvette. Stars aligned into neat, profitable rows, a giant was born and the CB750 quickly became a favorite of gearheads and weekenders everywhere. It’s been reported Honda topped 10-million in overall sales by the time the 750 was released, nevertheless, the factory was overwhelmed by demand and a price increase quickly followed. Improvements were made annually, and the successful works racers based on the CB 750 later became base models. A full analysis would fill volumes, but still wouldn’t be sufficient to cover every facet of a bike that redefined the street bike market.

1969 Honda CB750K
Fueled by passion, the 750 owes its existence to three key figures: founder/engineer Soichiro Honda, lead engineer Shoichiro Irimajin and Takeo Fujisawa, Honda’s brilliant marketing director. Forged by dreams of GP championships, Honda’s 1959 ascension into fame came from race winning four-strokes in various piston count, and Fujisawa’s massive advertising budget made sure everyone knew it. A perfect marriage of technology and keen marketing put Honda on top, aided greatly by an expanding global network established during the 1960s. The media handled Honda’s new offering with a mix of disbelief and awe, but all conclusions were favorable. Handsome in a way that appeals even now, the 750 grew dealerships and importers all across the continents, many who raced on Sunday and sold on Monday. Spares and service were readily available, but the SOHC 750 Four quickly earned a solid reputation for reliability.

The Honda’s stunning new engine was only part of the news. Other features emphasized in period adverts and tests were the electric starter, front disc brake and five speed transmission. Slightly undersquare at 61 x 63mm (bore x stroke) some asked why the factory didn’t fit twin camshafts (read: CB450). Several journos reported Honda decided the 8v, SOHC exotic enough with its four 28mm Keihin carbs and 4-into-4 exhaust. Translation: promoted as a sports bike, but engineered as a tourer. Deviating from normal practice with a dry sump design, those cases house twin primary chains to spin the 750’s multi-plate, wet clutch. A drive chain delivered the engine’s (claimed) 67-hp @8500 to the rear wheel.

Up top, the locknut valve adjusters are accessed via threaded plugs on each side of the rocker box. Good thing – there’s not enough clearance between the cover and frame tubes to remove it. Clearly, Honda’s concerns were two-fold; worried the engine’s power and increased braking force might distort the assembly, hence the compact dry-sump, close fit frame and stiff suspensions. Otherwise conventional, the chassis features 35mm telescopic forks (set at 27-degrees rake) and twin De Carbon shocks attaching to the 750’s ribbed swingarm. Bushings were used in the swingarm pivot. Made from chrome-plated steel the spoke wheels fit an 18-inch rear with 8” drum brake and a 19-inch front, a classic 60s design. Listed at 517-lb ready to ride the entire CB750 range averaged mid-13-second ¼-mile times and ran true to its 120-MPH top end claim. Note in this frame photo several rare CR-750 kit pieces, once sold by Honda.

1978 Honda CB750A “Automatic”
A sales disaster, the two-speed, hydro-drive CB750 followed another poor selling big bore automatic; Moto Guzzi’s V1000 Convert. Given its considerable success it is surprising Honda would follow Guzzi boss Alejandro De Tomaso down the hole, but it does show the Japanese giant capable of taking risks. Confirmed by American Honda, the automatic and CB750F were both developed together, the Super Sport launching in 1975, the 750A following in 1976. Tested by Cycle, the A’s longer swingarm and increased rake (28-degrees) slightly stretched wheelbase. Inside, new crankcases and covers were made for adapting the fluid drive, including wet sump lubrication. Wanting more bottom-end for the torque-converter transfer, compression was lowered to 8.6 and smaller (24mm) carbs fit. Sluggish from the start but reasonably perky elsewhere, editors raved about the A’s handling prowess, stability and ground clearance, courtesy of the new 4-into-1 exhaust. Other bits of interest include GoldWing alloy rims, new instrumentation, a fuel gauge and a push-button parking brake. 15.86 1/4-mile. 565-lb wet

1975-1978 Honda CB750F
Optimizing the line in many enthusiast’s eyes, Honda’s sporting CB750F revised the four into its original intent. Like the automatic, it was reconfigured with new bodywork and uprated chassis geometry, but this time with more power. The factory’s original line claimed the standard K and F used identical tuning, but it was later discovered engineers added a performance ignition curve, bumped compression and dropped the gearing substantially. Trending, a four-into-1 exhaust and rear disc were added, and while it isn’t confirmed Cycle was told areas of the frame used thicker tubing for added strength. Despite its trimmed exhaust and quicker spooling the F’s portly 540-lb kept it in the mid-13 second range. The truth? Honda’s changes transformed handling to such a degree, few cared.

Fit with alloy Comstar wheels, blacked-out graphics, triple disc brakes and some serious engine tweaking, 1977’s CB750F2 should have been the greatest of all. As the very foundation of the company for nearly ten-years perhaps Honda wanted to send the SOHC out with a bang…or at least give Suzuki owners something to think about. Reliability issues stained the otherwise brilliant F2, the result of a complete reworking of the cylinder head. Inlet valve diameters went from 32 to 34mm and exhaust 28 to 31mm, with stiffer springs. New cam timing added lift and duration, allowing safe revving to 10.000 rpm. To make room for the larger valve faces the included angle was increased, resulting in odd wearing guides, stems, oiling issues and even cam chain breakage. Dealers were besieged with warranty claims, Gaining yet another 25-lb mainly from the third disc and associated hardware, some period tests reported better times with the F1. Note: trailing brakes, recocated headlamp.  

Special frame: Fritz W. Egli
It’s fair to assume this editorial third shade would include Honda’s special order CR kit, which took the CB750 close to Daytona 200 form. Perhaps the CB750 F2 ‘Phil Read’ edition for Honda Britain, the Japauto 850cc special order machine from France, or a full Seeley build with Wisco 836cc kit and Lookheed brakes? All are worthy of increased coverage, including the factory twin-cam RCB works racers based on the production 750. Well documented, the list of luminaries that used the Honda four is a long one, with Rickman, Martin, Harris, and far more sharing Honda’s four-cylinder base. Nearly every spectrum of motorcycling was inspired by the SOHC 750 driveline; choppers, café builds, road racers, dragsters…all counting into the tens of thousands. The attraction? Not only was the 750 SOHC engine plentiful and trustworthy, but aftermarket support was unmatched. All of this found favor with Fritz W. Egli, the Swiss mastermind who adapted Honda’s inline four to his trademark beam frame.

According to Fritz, the Honda was his first venture outside the legendary Egli Vincent, and production moved from hot rod 60s style roadsters (which is the pattern of nearly every authentic Vincent-powered Egli) to full bodied Autobahn flyers. Welded with great care the CrMo tubing arches a 200mm backbone to connect front to back, holding the engine as a stressed member. Tubes drop and angle from the main beam to attach the engine’s factory mounting points, and hefty plates fit the swingarm pivot and controls. Only top components were added, typically (then) from Ceriani, Girling and Lockheed. Just one of many to experiment and succeed using the Honda, serious racing efforts saw the engineer work to reduce width and weight, as seen by this belt-driven alternator relocated behind the cylinder bank. More fours would follow from the Swiss master, but Honda’s CB750 four was his first.

There were few to compare when the Four took its first world tour. Yet, despite a healthy reputation the CB750 was never the big-bore speed king. It hung by the coattails of BSA’s Rocket 3 and the Mach III in 1970, only to lose sight of the acceleration leader when Kawasaki’s Z900 arrived. Truly, it is here where the Four’s place in history is solidified as for many, just being a Honda 750 was enough. While sales tapered when news of the twin-cam engine began to spread, the new bike cemented a huge movement of admiration for the original SOHC 750 Four, and lives on today. Anointed a classic the day after production ended, the unknowing recognize the CB 750’s simple silhouette as the visual definition of a motorcycle.

Whoever said excellence comes not from being noticed, but being remembered might have used Honda’s 1969 750 Four as inspiration. No motorcycle, from any era has equaled its impact. What else from 1969 could still be used as transportation today? The list is very short. I didn’t count total production, but enough were made to insure availability fifty-years past. Don’t delay, as prices for the entire range -not just the sandcast models- are rising. No question the four is considered a solid investment. Some being better than others, I’m torn to pick a production favorite, split equally between the classic low-bar CB750 K3 and the revised, modernized and streamlined Super Sport 750 F2. The look is timeless and the tone powered a generation of riders.  Following the 750 came even greater things, but history’s spotlight rightfully falls on the Honda CB750. Nolan Woodbury (Special thanks: TJ Jackson, Steve McIntyre, Mike Sorge, Mecum Auctions, American Honda)

Series production
CB750K0 (69-70)
CB750K1 (70-71)
CB750K2 (71-72)
CB750K3
CB750K4
CB750K5
CB750K6
CB750K7
CB750K8

CB750 F0 (1975)
CB750 F1 (1976)
CB750 F2 (1977)
CB750 F3 (1978)
http://www.sohc4.net/cb750/

Gallery

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