Honda CB 750 K (RC01)

Honda CB750K(Z)
	Honda CB 750 K
Manufacturer	Honda
Production	1978-1982
Predecessor	CB750 Four
Successor	CB 750 K (A); CB 750 K (B); CB 750 F
Class	Sport bike or standard
Engine	743 cc (45.3 cu in) DOHC air-cooled straight four
Top speed	125 mph (201 km/h)
Power	58 kW (78 hp) @ 9000 rpm
Torque	49 lbf⋅ft (66 N⋅m) @ 7000 rpm
Transmission	5-speed manual, chain final drive
Suspension	Front: telescopic forks ; Rear: swingarm with two spring/shock units.
Brakes	Front 275 mm double disc / Rear 180mm drum
Wheelbase	1,520 mm (60 in)
Dimensions	L: 2,200 mm (87 in); W: 880 mm (35 in); H: 1,160 mm (46 in);
Seat height	800 mm (31 in)
Weight	233 kg (514 lb) (dry);
Fuel capacity	20 L (4.4 imp gal; 5.3 US gal)
Fuel consumption	7.3 L (1.6 imp gal; 1.9 US gal) per 100 km (62 mi)

The CB 750 K(Z) (model RC01) is a motorcycle model by the Japanese vehicle manufacturer Honda.

The new 750

At the 1978 IFMA in Cologne the new CB 750 was presented as the successor to the CB 750 four for Europe and available for sale later that year. With a new DOHC engine design and numerous other new features it was presented as "what happens when you keep winning races".^[4]

New features

The DOHC 16 valve engine was based on the engine in the RCB943 and RCB997 featuring four valves per cylinder, and next to the timing chain driving the exhaust cam, a second chain driving the intake cam. ^[5] The engine was also better balanced by moving the alternator from the left to the right side. ^[6]

Next to the new engine, new features like the transistorized ignition system was promising smooth performance and greater economy. It had increased braking performance with double discs up front and a lower, deeply padded seat for greater riding comfort and handling. Increased suspension travel for the front forks and rear FVQ damper, and a taper roller bearing for the head for smoother riding. Improved safety features like an H4 headlamp and double rear brake light bulbs were also advertised.^[4]

Technical details

Sources:^[2]^[1]

Engine and power transmission

Air-cooled 4-cylinder 4-stroke engine with chain driven camshaft (DOHC), 4 valves per cylinder (total of 16), via tappets actuated
Power: 57 kW (77 hp at 9,000 min -1 .), Max torque 66 Nm at 7000 min -1
Average piston speed : 2.07 m / s per 1,000 min −1
Top speeds: 200 km / h (lying solo), 187 km / h (sitting solo), 179 km / h (with pillion passenger)
743 cm³ displacement with 62 mm (2.4 in) bore and 62 mm (2.4 in) stroke
Compression ratio 9: 1
Electric starter
Contactless transistor-controlled battery ignition with mechanical centrifugal force adjustment
Pressure circulation lubrication
One-piece steel crankshaft with 5 sliding bearings
4 Keihin equal pressure carburetors with a diameter of 30 mm (1.2 in)
Wet multi-plate clutch
Constant-mesh 5-speed gear
Three-phase - alternator (260 Watt at 5000 min -1 ), battery (12 V / 14 Ah)
4-in-4 exhaust system (sometimes shown as 4-in-2-in-4)
Primary drive via inverted tooth chain
Secondary drive via roller chain

Frame

Double-loop tubular steel frame with a single-sided unscrewable support on the right for (dis) assembly of the motor
Rear swing arm stored in plastic bushings (needle roller bearings from the end of 1980)
Ground clearance 150 mm (5.9 in)
Foot peg height 355 mm (14.0 in)
Hydraulically damped telescopic fork at the front (35 mm (1.4 in)) with 160 mm (6.3 in) travel
2 hydraulically damped spring struts at the rear, springs adjustable in 5 positions
Double 275 mm (10.8 in) disc brake with single-piston calipers at the front
Simplex drum brake 180 mm (7.1 in) at the rear
Comstar aluminum wheels with tubeless tires (3.25-19 / 4.00-18)
20 L (4.4 imp gal; 5.3 US gal) steel tank

Colors

The CB 750 K (Z) was available in four base colors: blue, black, red and brown.

Color code	Name	Implementation
R-104C-U	Candy Muse Red/Candy Burgundy	Metallic paint with gold or light red striping
YR-106C-U	Candy Bayard Brown	Metallic brown with gold striping (Canada only)
PB-107C-U	Candy Tanzanight Blue	Metallic blue with gold striping
NH-1	Black	Black with red striping

References

^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k "Launched Honda CB750K, a large 4-cylinder two-wheeled vehicle with "comfortable driving" and "light maneuverability"", Honda press release, December 12, 1978
^ ^a ^b ^c ^d ^e Honda CB750K Service Manual, (Honda Motor Co., Ltd.), 1978
^ Honda CB750 & CB900 dohc fours 1978 to 1984 Owners Workshop Manual, Haynes_Manual, 2015, ISBN 978-1-85010-217-5
^ ^a ^b Ker, Rod (2015), Honda CB750 four, Amberley_Publishing, ISBN 978-1-4456-5121-7
^ "Honda Comes Back Strong". Cycle World. January 1, 1979.
^ "Honda CB750K, A Sophisticated Successor to Honda's Traditional 750". Cycle World. January 1, 1979.

[HondaPR-1] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k "Launched Honda CB750K, a large 4-cylinder two-wheeled vehicle with "comfortable driving" and "light maneuverability"", Honda press release, December 12, 1978

[manual-2] Honda CB750K Service Manual, (Honda Motor Co., Ltd.), 1978

[Haynes-3] Honda CB750 & CB900 dohc fours 1978 to 1984 Owners Workshop Manual, Haynes_Manual, 2015, ISBN 978-1-85010-217-5

[RodKer-4] Ker, Rod (2015), Honda CB750 four, Amberley_Publishing, ISBN 978-1-4456-5121-7

[CW1-5] "Honda Comes Back Strong". Cycle World. January 1, 1979.

[CW2-6] "Honda CB750K, A Sophisticated Successor to Honda's Traditional 750". Cycle World. January 1, 1979.

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