Honda CB750K 1978

1978 Honda CB750K Specs, Features & Pictures Gallery

Honda CB750K 1978
ホンダ / Honda CB750K photo, model year 1978.
A 4-cylinder 750cc bigbike with comfort driving and light handling.

Honda released a big sports motorcycle model, Honda CB750K equipped with a newly designed 4-cylinder 16-valve DOHC engine with numerous precise mechanisms from December 13, 1978.

1978 CB750K Motorcycle Profile:
Ten years after the birth of 750cc series, Honda chose the DOHC engine based on the 900cc for the new generation 750cc engine. First, in 1978, the CB900F for the overseas market was released, and at the same time, the Honda CB750K with a somewhat cruiser-style styling appeared for the domestic market. It is a "transition to F" model with a new 4-cylinder engine but 4 mufflers. Price at the time of release was 498,000 yen

A newly designed 4-cylinder 16-valve DOHC engine was mounted on a newly designed frame. Although it is a high-speed unit that generates 65ps at 9,000 rpm from a displacement of 748cc, it also uses a new exhaust collection system to generate powerful torque even at low and medium speeds. A transistor type was adopted for the ignition method, and maintenance was also simplified.

The engine of the Honda CB750K was developed based on the Honda RCB (997CC), which has won the European championship two-wheel endurance race for three consecutive years. be able to.
In addition, the newly designed frame and appropriate suspension provide light maneuverability and calm dignity, making it an easy-to-handle large motorcycle suitable for a wide range of diversified applications. (Compliant with the 1979 noise regulation)
In addition, the CB750 series has been a favorite among users around the world as the mainstream of multi-cylinder engine motorcycles for 10 years since its first release in 1969. By the end of October this year, the CB750 series It produces 670,000 units.

1978 Honda CB750K Price

Standard Cash Price was 498,000 yen (in 1978 at Japan excluding Hokkaido and some remote islands).
Production plan: 4,500 units per month (including exports).

Main Features


The air-cooled 4-cycle 4-cylinder DOHC engine has 4 valves per cylinder and has a maximum output of 65 horsepower / 9000 rpm from a displacement of 748 cc. Despite its high output and high revs, it has smooth characteristics from low to medium speed to high speed, and can always run with plenty of margin from city areas to highways.
In addition, the use of a non-contact type transistor ignition device eliminates the need for point inspection and maintenance, and provides stable, strong ignition.

Frame Suspension

The newly designed lightweight and strong double cradle frame, which enables a low seat height, combined with a suspension with excellent road-following and shock-absorbing properties, allows you to enjoy light and comfortable riding. can.


The streamline flowing from the tank to the side covers and the four mufflers that flow dynamically from the beautifully sculpted engine create a stately design.


  • Engine parts such as 2-stage silent cam chain, hi-bo chain, and hydraulic tensioner are all quiet. It is a quiet DOHC engine.
  • A new collective exhaust system is adopted for the four mufflers. Due to the mutual interference of the exhaust flows, it not only provides strong torque even in the low and medium speed range, but also enhances the noise reduction effect.


  • The combination meter panel is laid out for easy viewing and handling. A new type of rearview mirror that provides a clear rear view with less blurring. Detailed considerations have been made, such as new pattern tubeless tires that improve stability when driving in the rain.

1978 Honda CB750K Main Specifications

The CB750K, which debuted in 1978, was equipped with a new DOHC (twin cam) 16-valve engine. It was developed based on the 997cc unit for the endurance racer RCB. The displacement is 748cc, and although it is the same as the air-cooled 4-cylinder, the DOHC head and the number of valves per cylinder are also 4 as mentioned above. This new engine was also installed in the CB750F that appeared in 1979. In 1980, a minor change was made with a double disc front brake.

Motorcycle nameCB750K
Total length (m)2.225
Width (m)0.885
Total height (m)1.150
Length (m)1.515
Vehicle Weight (Kg)Maintenance:250,Drying:231
Minimum turning radius (m)2.6
Fuel tank capacity (L)20
Fuel consumption rate (km/L)
(60km/h level running test value)
Slope climbing ability (tanθ)0.46
Engine typeAir-cooled 4-cycle DOHC 4-cylinder
Total Displacement (cm3 )748
Inner Diameter x Stroke (mm)62.0×62.0
Compression Ratio9.0
Max Power (PS/rpm)65/9,000
Max Torque (Kg-m/rpm)5.9/7,000
Starting methodSelf-operated
Lubrication methodCombination of pressure feed type and splash type
Lubricant capacity (L)4.5
Primary reduction ratio2.381
Transmission ratio1st2.533
2 speed1.789
3 speed1.391
4 speed1.160
5 speed0.964
Final gear ratio2.388
Frame formatDouble cradle format
Suspension methodFrontTelescopic method
RearSwing arm type
Caster (degrees)27°30′
Trail (mm)117
Tire SizeFront3.25H19-4PR Tubeless
Rear4.00H18-4PR tubeless
Brake typeFrontHydraulic disc
RearRod type leading trailing

1980 model Honda CB750K

The front brake, which was a single disc, has become a double disc. This was the same specification as the new American cruiser model "750 Custom Exclusive" that appeared at the same time.


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