Honda CB750 SOHC Service Manual (1969-1978) – Partial Scan

Honda launched the CB750 FOUR in 1969 after American Honda asked for a larger four-cylinder motorcycle with strong performance, four carburetors and four exhausts. Honda drew on its Grand Prix racing experience to create a 736 cc air-cooled SOHC inline-four with a front hydraulic disc brake, technologies that were exceptional on a mass-produced motorcycle at the time. Honda’s own history describes the CB750 FOUR as the world’s first mass-produced 750 cc four-stroke four-cylinder OHC motorcycle with a front disc brake, and credits it with changing expectations for large road motorcycles: Honda CB750 FOUR history.

The original specification used a 61.0 × 63.0 mm bore and stroke for 736 cc, 9.0:1 compression, four carburetors, a five-speed constant-mesh transmission and chain final drive. A double-cradle tubular-steel frame, telescopic fork and swingarm rear suspension gave the machine conventional architecture around an unusually sophisticated engine. The combination made the CB750 an influential air-cooled SOHC four-cylinder motorcycle, capable of both high-speed road use and long-distance touring while remaining relatively easy to maintain compared with many contemporary large-capacity machines.

The platform evolved steadily through the K-series during the 1970s. Honda revised detail specifications, chassis equipment, styling and braking while keeping the same fundamental 736 cc SOHC engine layout. As competition intensified, the range broadened beyond the standard K models to sportier F derivatives. Depending on market and model year, later SOHC 750s adopted features such as revised exhaust systems, rear disc brakes and Honda Comstar wheels. Honda’s 1977 material shows the CB750 FOUR-K and CB750 FOUR-II as the final Japanese-market SOHC models, with the FOUR-II using a 4-into-1 exhaust and Comstar wheels.

The SOHC CB750 also built a strong competition reputation. Honda records wins in the 1969 Suzuka 10 Hours, the 1969 Bordeaux 24 Hours and the 1970 Daytona 200, reinforcing the model’s image as more than a touring road bike. By the late 1970s, however, rivals had moved the performance benchmark forward and Honda’s endurance-racing experience with the RCB1000 led toward a new generation. For 1979 Honda introduced a four-valve DOHC CB750F/CB750K family derived from that racing development, creating a clear mechanical break from the earlier SOHC machines. See Honda’s 1979 CB750F/CB900F development history.

The factory publication represented here was compiled to cover the SOHC CB750 and CB750F family through the late 1970s. Its foreword lists the original CB750 plus K1-K7, 1978 K, and F-series variants through 1978, supporting the 1969-1978 catalog range. The downloadable file itself is only a 46-page partial scan and ends during the engine-mechanical section, so this product is identified accordingly rather than being presented as the complete shop manual. Related publications are grouped in the Honda CB750 service manual catalog.