CB750K

“1969 CB750”

History

The CB750 was an historic motorcycle often recognized as the most important motorcycle of the 20th Century. From this revolutionary bike, Honda developed a complete line of reliable four cylinder motorcycles to become the largest motorcycle company in the world and usher in an era of Japanese dominance in the industry.

The CB750 was available in several variations, the CB750K which retained the classic four-into-four pipes and styling of the original 1969 model. The CB750F which adopted the four-into-one pipes and cafe racer stylings popularized by the CB400F. And the CB750A, mating the 750 engine to an automatic gearbox.

The CB750 had a production run of 9 years during which a total of, roughly, 553,400 motorcycles were made. The K1 was the most popular single model with sales figures of about 77,000. The second most popular model, the K2, also sold in large numbers, a total of 63,500, due primarily to the fact that this model was in production until 1976 in all markets except the US and Japan.

The first 7,414 bikes produced had sandcast engines. The identification of these models, which are in great demand amongst collectors, is a bit of a science and is covered in this section of the site.

Model Changes

Year Model Changes
1969 This is the original version of the CB750. Notable differences from later models include louvered side panels, all-cable throttles, plastic instrument lenses and a duck-tail (humped) seat. The first 7400 or so bikes had ‘sand-cast’ crankcases.
1971 Beam-operated throttles; re-styled airbox and oil tank with new emblems; white tank lettering; black front caliper.
1972 K2 with restricted silencers; altered rear shocks; metal chainguard; warning light panel between the instruments.
1973 K3 introduced in the US; K2 continues elsewhere. Improved front forks and five-way adjustable shocks. The K3 had new tank graphics, restricted air intake, front disc water guard, and running lights in the indicators.
1974 K4 for the US and Japan; K2 elsewhere. Only 3 vertical braces in cylinder head side fins. The K4 added a ratio indicator on the gearbox.
1975 K5 for the US; K2/K4 elsewhere. The K5 got bigger indicators and a rubber-tipped flip-up side stand.
1976 K6 with stronger swing-arm; detuned engine; no chain oiler.
1977 K7 with F1-style engine and single carburettor accelerator pump; plainer silencers; 17 inch rear wheel with wider tire; O-ring chain; flush fuel filler.
1978 K8 for the US with two-tier seat; minor engine changes.

Serial Numbers

CB750 Serial Numbers
The frame serial number (fig 1.1) is stamped on the left side of the steering head pipe and the engine serial number (fig 1.2) is located on the top of the crankcase left side. The serial numbers do not match, but are in the same model series. It is not uncommon to find CB750’s which have a replacement engine from a different model year since engines from all of the CB750K models are compatible with all of the frames.
Model Year Production Dates Number Sold Engine# Frame#
CB750 Sandcast 1969/70 1969 – 1970 7,414 1000001-1007414 1000001
CB750 K0 1970 1970 53,400 1007414 1000001-1044649
CB750 K1 1971 08/70 – 11/71 77,000 1044806 1044650
CB750 K2 1972 11/71 – 09/72 63,500 2000001 2000001
CB750 K3 1973 09/72 – 06/73 38,000 2200001 2200001
CB750 K4 1974 06/73 – 05/74 60,000 2300001 2300001
CB750 K5 1975 05/74 – 12/74 35,000 2372115 2500001
CB750 K6 1976 12/74 – 06/76 42,000
US 2428762–2465510 2540001–2575894
Canada 2428762–2465992 2540001–2576394
European Direct 2438827–2475324 2556099–2584973
France 2438827–2474663 2555545–2584393
Germany 2438827–2476626 2550437–2586393
England 2438827–2475216 2573735–2584843
General Export KPH 2438827–2476422 2573735–2584843
Australia 2438827–2476604 2578674–2586269
CB750 K7 1977 06/76 – 05/77 38,000
US 2700009–2729740 2700009–2729532
Canada 2709652–2728188 2709636–2728111
General Export KPH 2720001–2740319 2719942–2739004
General Export MPH 2732065–2732824 2731270–2732029
England 2719995–2736452 2719935–2735472
European Direct 2720004–2740102 2719941–2738818
France 2719999–2738337 2719939–2737053
Germany 2719997–2737988 2719937–2736904
Australia 2720003–2740319 2719944–2739038
CB750 K8 1978 05/77 – 05/78 36,000
USA 3000001–3062980 2800001–2862980
Canada 3001934–3061938 2801946–2861935

CB750K0

Model Guide

Candy Blue Green Candy Gold Candy Ruby Red

The K0 was available in three colors, Candy Gold, Candy Ruby Red, and Candy Blue Green. The tank, side covers, fork uppers and headlight shell were painted the same color as the tank. The most distinctive mechanical feather are a throttle linkage which used separate cables to each carb.

Engine # Changes
1000140 Bolt at the final drive changed from M8x80 to M10x82
1000220 New lower case, engine case only available as set
1000425 Transmission changed for better shifting
1001081 New crankshaft
1001760 7 instead of 8 clutch disks
1003528 New final drive shaft and sprocket
1005307 Revised right bearing of main tranny shaft
1007220 New lower case, deeper oil pan
1007415 Introduction of circular opening in lower case
1007500 End of sandcast engines
1009554 Finned oil filter casing
1010336 Additional oil passages, new rocker shafts and valve cover
1014996 Revised exhaust valve guides & valve guide seals
1026144 new cylinder head, cylinder block: new central M6 bolt, cyl. block w/8 rubbers. Case with guard to prevent damages from broken drive chains. New sprocket cover, new shift mechanism
1042806 Weaker clutch springs

Specifications

Item English Metric
Dimensions
Overall length 85.0 in. 2,160 mm
Overall width 34.8 in. 885 mm
Overall height 45.5 in. 1,155 mm
Wheel base 57.3 in 1,455 mm
Seat height 31.5 in. 800 mm
Foot Peg Height 12.2 in. 310 mm
Ground Clearance 5.5 in. 160 mm
Curb weight 517.3 lb 235 kg
Weight distribution L/R 271.1/209.5 lb 123/205 kg
Frame & Suspension
Type Double cradle tubular steel
Front
Fork travel 5.6 in. 143mm
Caster Angle 63º
Trail length 3.74 in. 95mm
Oil capacity (dry) 7.5-7.8 oz 220-230 cc
Oil capacity (full) 6.9-7.1 oz 200-210 cc
Rear Swing arm, travel 3.3 in. 85mm
Front Tire 3.25-19 (4PR) Rib tire
Rear Tire 4.00-18 (4 PR) Block tire
Brakes
Front Type Disk
Front lining swept area 59.3 sq in 382.9 sq cm
Rear Type Internal expanding shoe
Rear lining swept area 34.2 sq in 220.5 sq cm
Fuel
Tank Capacity 4.7 US gal, 3.9 Imp gal 18 liter
Reserve Capacity 1.3 US gal, 1.1 Imp. gal 5 liter
Carburetor
Type Venturi Diaphram, 4x28mm Keihin, slide type
Air screw opening 1 1/8 turn
Idle speed 900 rpm
Main jet #120
Idle jet #40
Air jet #100
Carb main bore 1.102in. 28mm
Engine
Type Air-cooled, 4-stroke, O.H.C. engine
Cylinder Arrangement 4-cylinder in line
Bore and Stroke 2.402x2.480 in. 61x63 mm
Displacement 44.9135 cu in 736 cc
Compression Ratio 9.0:1
Cylinder head compression 170.7 psi 12 kg/cm sq
Maximum Horsepower 67 BHP@8,000 rpm
Maximum Torque 44.12 lb-ft@7,000 rpm 6.1 kg-m@7,000 rpm
Valve train Chain driven overhead camshaft
Oil Capacity 3.7 US qt, 3.1 Imp. qt 3.5 liter
Oil Tank Capacity 2.1 US qt., 1.8 Imp. qt 2 liter
Lubrication System Forced pressure and dry sump
Air filtration Paper element
Valve Timing
Intake Valve Open At 5º before top dead center
Intake Valve Close At 30º after bottom dead center
Exhaust Valve Open At 35º before bottom dead center
Exhaust Valve Close At 5º after top dead center
Valve Tappet Clearance
Intake 0.002in. 0.05mm
Exhaust 0.003in. 0.08mm
Engine weight (Wet) 176.3 lb 80 kg
Drive Train
Clutch Wet, multi-plate
Transmission Type 5-speed, constant mesh
Gear Ratio I 2.500:1
Gear Ratio II 1.708:1
Gear Ratio III 1.333:1
Gear Ratio IV 1.097:1
Gear Ratio V 0.939:1
Primary reduction 1.708:1
Secondary reduction 1.167:1
Final Reduction 2.667:1 (18T x 48T)
Electrical
Type 12v, negative earth
Ignition Coil and contact breaker, spare spark
Starting system Electrical motor and kick pedal
Alternator Three phase A.C. generator 12V/0.21kW@5,000 rpm
Battery Capacity 12V - 14 amp hour
Spark plug type NGK D-8ES
Spark plug gap 0.024 ~ 0.028 in. 0.6 ~ 0.7 mm
Point gap 0.012 ~ 0.016 in. 0.3 ~ 0.4 mm

CB750K1

Model Guide

Garnet Brown Gold Valley Green Metallic Candy Ruby Red

The CB750K1 was sold in four different color schemes, Candy Gold, Candy Ruby Red, Candy Garnet Brown, and Valley Green Metallic. This model featured a single paint color for the tank, side covers, fork uppers and headlight shell. The side covers were smaller than the K0 without slots on the leading edge.  The throttle linkage changed to a cable-controlled shaft joining the four carbs together.

Engine # Changes
1044805 New case, final drive 18/48 i/o 16/45 or 17/45, chain oiler
1044812 Carburetors linked instead of individual cables
1044968 Improved neutral position
1056080 New clutch basket
1064903 Introduction of special washerless bolts
1068376 Clamp for scavange hoses
1071336 Fuel hoses 5.5mm dia. instead of 5.0mm
1113723 Grooves in gear shift drum changed from 0.5mm to 1mm for 4th
and 5th gear
1114461 New head gasket

Specifications

Item English Metric
Dimensions
Overall length 85.0 in. 2,160 mm
Overall width 34.8 in. 885 mm
Overall height 45.5 in. 1,155 mm
Wheel base 57.3 in 1,455 mm
Seat height 31.5 in. 800 mm
Foot Peg Height 12.2 in. 310 mm
Ground Clearance 5.5 in. 160 mm
Curb weight (dry) 479 lb 218 kg
Weight distribution L/R 271.1/209.5 lb 123/205 kg
Frame & Suspension
Type Double cradle tubular steel
Front
Fork travel 5.6 in. 143mm
Caster Angle 63º
Trail length 3.74 in. 95mm
Oil capacity (dry) 7.5-7.8 oz 220-230 cc
Oil capacity (full) 6.9-7.1 oz 200-210 cc
Rear Swing arm, travel 3.3 in. 85mm
Front Tire 3.25-19 (4PR) Rib tire, 28psi
Rear Tire 4.00-18 (4 PR) Block tire, 28psi
Brakes
Front Type Disk
Front lining swept area 59.3 sq in 382.9 sq cm
Rear Type Internal expanding shoe
Rear lining swept area 34.2 sq in 220.5 sq cm
Fuel
Tank Capacity 4.5 US gal, 3.7 Imp. gal 17 liter
Reserve Capacity 1.3 US gal, 1.1 Imp. gal 5 liter
Carburetor
Type Piston Valve, Keihin, slide type
Setting mark 7A
Air screw opening 1 3/8 turns
Idle speed 950 rpm
Main jet #120
Idle jet #40
Float height 0.866 in. 26mm
Engine
Type Air-cooled, 4-stroke, O.H.C. engine
Cylinder Arrangement 4-cylinder in line
Bore and Stroke 2.402x2.480 in. 61x63 mm
Displacement 44.9135 cu in 736 cc
Compression Ratio 9.0:1
Cylinder head compression 170.7 psi 12 kg/cm sq
Maximum Horsepower 67 BHP@8,000 rpm
Maximum Torque 44.12 lb-ft@7,000 rpm 6.1 kg-m@7,000 rpm
Valve train Chain driven overhead camshaft
Oil Capacity 3.7 US qt, 3.1 Imp. qt 3.5 liter
Oil Tank Capacity 2.1 US qt., 1.8 Imp. qt 2 liter
Lubrication System Forced pressure and dry sump
Air filtration Paper element
Valve Timing
Intake Valve Open At 5º before top dead center
Intake Valve Close At 30º after bottom dead center
Exhaust Valve Open At 35º before bottom dead center
Exhaust Valve Close At 5º after top dead center
Valve Tappet Clearance
Intake 0.002in. 0.05mm
Exhaust 0.003in. 0.08mm
Engine weight (Wet) 176.3 lb 80 kg
Drive Train
Clutch Wet, multi-plate
Transmission Type 5-speed, constant mesh
Gear Ratio I 2.500:1
Gear Ratio II 1.708:1
Gear Ratio III 1.333:1
Gear Ratio IV 1.097:1
Gear Ratio V 0.939:1
Primary reduction 1.708:1
Secondary reduction 1.167:1
Final Reduction 2.667:1 (18T x 48T)
Electrical
Type 12v, negative earth
Ignition Coil and contact breaker, spare spark
Starting system Electrical motor and kick pedal
Alternator Three phase A.C. generator 12V/0.21kW@5,000 rpm
Battery Capacity 12V - 14 amp hour
Spark plug type NGK D8ES-L, NDX 24ES
Spark plug gap 0.024 ~ 0.028 in. 0.6 ~ 0.7 mm
Point gap 0.012 ~ 0.016 in. 0.3 ~ 0.4 mm
Headlight Low/high 12V 40W/50W
Tail/stoplight 12V 7W/23W (SEA Trade No. 1157)
Turn signal bulb Front/rear 12V 23W/23W
Speedometer bulb 12V 3W
Tachometer bulb 12V 3W
Neutral indicator bulb 12V 3W
Turn signal indicator bulb 12V 3W
High beam indicator bulb 12V 3W

CB750K2

Model Guide

Flake Sunrise Orange Candy Gold Brier Brown Metallic

The K2 model, introduced in November 1971, was available in Flake sunrise Orange, Candy Gold, and Brier Brown Metallic paint. The gas tank featured a gold stripe. The upper forks were chrome. The headlight shell was black. The taillight and side reflectors were larger in size.

Engine # Changes
2061311 Shorter oil hose w/white mark. Main jets 110, smaller cutouts in air filter case

Specifications

Item English Metric
Dimensions
Overall length 85.6 in. 2,175 mm
Overall width 34.3 in. 870 mm
Overall height 46.1 in. 1,170 mm
Wheel base 57.3 in 1,455 mm
Seat height 31.9 in. 810 mm
Foot Peg Height 12.2 in. 310 mm
Ground Clearance 5.5 in. 140 mm
Curb weight (dry) 479 lb 218 kg
Weight distribution L/R 271.1/209.5 lb 123/205 kg
Frame & Suspension
Type Double cradle tubular steel
Front
Fork travel 5.6 in. 143mm
Caster Angle 63º
Trail length 3.74 in. 95mm
Oil capacity (dry) 7.5-7.8 oz 220-230 cc
Oil capacity (full) 5.3-5.4 oz 155-160cc
Rear Swing arm, travel 3.3 in. 85mm
Front Tire 3.25-19 (4PR) Rib tire, 28psi
Rear Tire 4.00-18 (4 PR) Block tire, 28psi
Brakes
Front Type Disk
Front lining swept area 59.3 sq in 382.9 sq cm
Rear Type Internal expanding shoe
Rear lining swept area 34.2 sq in 220.5 sq cm
Fuel
Tank Capacity 4.5 US gal, 3.7 Imp. gal 17 liter
Reserve Capacity 1.3 US gal, 1.1 Imp. gal 5 liter
Carburetor
Type Piston Valve, Keihin, slide type
Setting mark 7A
Air screw opening 1 3/8 turns
Idle speed 950 rpm
Main jet #120
Idle jet #40
Float height 0.866 in. 26mm
Engine
Type Air-cooled, 4-stroke, O.H.C. engine
Cylinder Arrangement 4-cylinder in line
Bore and Stroke 2.402x2.480 in. 61x63 mm
Displacement 44.9135 cu in 736 cc
Compression Ratio 9.0:1
Cylinder head compression 170.7 psi 12 kg/cm sq
Maximum Horsepower 67 BHP@8,000 rpm
Maximum Torque 44.12 lb-ft@7,000 rpm 6.1 kg-m@7,000 rpm
Valve train Chain driven overhead camshaft
Oil Capacity 3.7 US qt, 3.1 Imp. qt 3.5 liter
Oil Tank Capacity 2.1 US qt., 1.8 Imp. qt 2 liter
Lubrication System Forced pressure and dry sump
Air filtration Paper element
Valve Timing
Intake Valve Open At 5º before top dead center
Intake Valve Close At 30º after bottom dead center
Exhaust Valve Open At 35º before bottom dead center
Exhaust Valve Close At 5º after top dead center
Valve Tappet Clearance
Intake 0.002in. 0.05mm
Exhaust 0.003in. 0.08mm
Engine weight (Wet) 176.3 lb 80 kg
Drive Train
Clutch Wet, multi-plate
Transmission Type 5-speed, constant mesh
Gear Ratio I 2.500:1
Gear Ratio II 1.708:1
Gear Ratio III 1.333:1
Gear Ratio IV 1.097:1
Gear Ratio V 0.939:1
Primary reduction 1.708:1
Secondary reduction 1.167:1
Final Reduction 2.667:1 (18T x 48T)
Electrical
Type 12v, negative earth
Ignition Coil and contact breaker, spare spark
Starting system Electrical motor and kick pedal
Alternator Three phase A.C. generator 12V/0.21kW@5,000 rpm
Battery Capacity 12V - 14 amp hour
Spark plug type NGK D8ES-L, NDX 24ES
Spark plug gap 0.024 ~ 0.028 in. 0.6 ~ 0.7 mm
Point gap 0.012 ~ 0.016 in. 0.3 ~ 0.4 mm
Headlight Low/high 12V 40W/50W
Tail/stoplight 12V 3/32 CP (SAE Trade No. 1157)
Turn signal bulb 12V 32/32 CP (SAE Trade no. R1034, L1073)
Speedometer bulb 12V 2CP (SAE Trade No. 57)
Tachometer bulb 12V 2CP (SAE Trade No. 57)
Neutral indicator bulb 12V 2CP (SAE Trade No. 57)
Turn signal indicator bulb 12V 2CP (SAE Trade No. 57)
High beam indicator bulb 12V 2CP (SAE Trade No. 57)
Position light 12V 4CP

CB750K3

Model Guide

Flake Sunrise Orange Maxim Brown Metallic Candby Bucchus Olive

The 1973 CB750K3 was only available in the US as the K2 continued for a few more years in other markets. This model was offered in three colors, Flake Sunrise Orange, Maxim Brown Metallic, and Candy Bucchus Olive. The gas tank stripes were white, gold and black.

Engine # Changes
2200001 New cylinder head, new valve guide seals, improved oil passages to camshaft, new piston rings (three part oil scavenge rings), new cam chain guide, larger piston pin circlips, new final drive shaft, new sprocket cover
2228679 New cylinder head, new valve guides, new valve guide seals, no more rubbers between fins

Specifications

Item English Metric
Dimensions
Overall length 85.6 in. 2,175 mm
Overall width 34.3 in. 870 mm
Overall height 46.1 in. 1,170 mm
Wheel base 57.3 in 1,455 mm
Seat height 31.9 in. 810 mm
Foot Peg Height 12.2 in. 310 mm
Ground Clearance 5.5 in. 140 mm
Curb weight (dry) 479 lb 218 kg
Weight distribution L/R 271.1/209.5 lb 123/205 kg
Frame & Suspension
Type Double cradle tubular steel
Front
Fork travel 5.6 in. 143mm
Caster Angle 63º
Trail length 3.74 in. 95mm
Oil capacity (dry) 7.5-7.8 oz 220-230 cc
Oil capacity (full) 5.3-5.4 oz 155-160cc
Rear Swing arm, travel 3.3 in. 85mm
Front Tire 3.25-19 (4PR) Rib tire, 28psi
Rear Tire 4.00-18 (4 PR) Block tire, 28psi
Brakes
Front Type Disk
Front lining swept area 59.3 sq in 382.9 sq cm
Rear Type Internal expanding shoe
Rear lining swept area 34.2 sq in 220.5 sq cm
Fuel
Tank Capacity 4.5 US gal, 3.7 Imp. gal 17 liter
Reserve Capacity 1.3 US gal, 1.1 Imp. gal 5 liter
Carburetor
Type Piston Valve, Keihin, slide type
Setting mark 7A
Air screw opening 1 3/8 turns
Idle speed 950 rpm
Main jet #105
Idle jet #40
Float height 0.866 in. 26mm
Engine
Type Air-cooled, 4-stroke, O.H.C. engine
Cylinder Arrangement 4-cylinder in line
Bore and Stroke 2.402x2.480 in. 61x63 mm
Displacement 44.9135 cu in 736 cc
Compression Ratio 9.0:1
Cylinder head compression 170.7 psi 12 kg/cm sq
Maximum Horsepower 67 BHP@8,000 rpm
Maximum Torque 44.12 lb-ft@7,000 rpm 6.1 kg-m@7,000 rpm
Valve train Chain driven overhead camshaft
Oil Capacity 3.7 US qt, 3.1 Imp. qt 3.5 liter
Oil Tank Capacity 2.1 US qt., 1.8 Imp. qt 2 liter
Lubrication System Forced pressure and dry sump
Air filtration Paper element
Valve Timing
Intake Valve Open At 5º before top dead center
Intake Valve Close At 30º after bottom dead center
Exhaust Valve Open At 35º before bottom dead center
Exhaust Valve Close At 5º after top dead center
Valve Tappet Clearance
Intake 0.002in. 0.05mm
Exhaust 0.003in. 0.08mm
Engine weight (Wet) 176.3 lb 80 kg
Drive Train
Clutch Wet, multi-plate
Transmission Type 5-speed, constant mesh
Gear Ratio I 2.500:1
Gear Ratio II 1.708:1
Gear Ratio III 1.333:1
Gear Ratio IV 1.097:1
Gear Ratio V 0.939:1
Primary reduction 1.708:1
Secondary reduction 1.167:1
Final Reduction 2.667:1 (18T x 48T)
Electrical
Type 12v, negative earth
Ignition Coil and contact breaker, spare spark
Starting system Electrical motor and kick pedal
Alternator Three phase A.C. generator 12V/0.21kW@5,000 rpm
Battery Capacity 12V - 14 amp hour
Spark plug type NGK D8ES-L, NDX 24ES
Spark plug gap 0.024 ~ 0.028 in. 0.6 ~ 0.7 mm
Point gap 0.012 ~ 0.016 in. 0.3 ~ 0.4 mm
Headlight Low/high 12V 40W/50W
Tail/stoplight 12V 3/32 CP (SAE Trade No. 1157)
Turn signal bulb 12V 32/32 CP (SAE Trade no. R1034, L1073)
Speedometer bulb 12V 2CP (SAE Trade No. 57)
Tachometer bulb 12V 2CP (SAE Trade No. 57)
Neutral indicator bulb 12V 2CP (SAE Trade No. 57)
Turn signal indicator bulb 12V 2CP (SAE Trade No. 57)
High beam indicator bulb 12V 2CP (SAE Trade No. 57)
Position light 12V 4CP

CB750K4

Model Guide

Boss Maroon Metallic Flake Sunrise Orange Freedom Green Metallic

The CB750 K4 was available only in the US and Japan and was offered in three colors: Boss Maroon Metallic, Flake Sunrise Orange, Freedom Green Metallic. The gas tank stripes were white, gold and black and wider than previous years. The speedometer displayed 20mph increments.

Engine # Changes
2304501 Smaller cam chain tunnel
2352923 New cylinder block
2348093 Crankcase cover gear indicator

Specifications

Item English Metric
Dimensions
Overall length 85.6 in. 2,175 mm
Overall width 34.3 in. 870 mm
Overall height 46.1 in. 1,170 mm
Wheel base 57.3 in 1,455 mm
Seat height 31.9 in. 810 mm
Foot Peg Height 12.2 in. 310 mm
Ground Clearance 5.5 in. 140 mm
Curb weight (dry) 479 lb 218 kg
Weight distribution L/R 271.1/209.5 lb 123/205 kg
Frame & Suspension
Type Double cradle tubular steel
Front
Fork travel 5.6 in. 143mm
Caster Angle 63º
Trail length 3.74 in. 95mm
Oil capacity (dry) 7.5-7.8 oz 220-230 cc
Oil capacity (full) 5.3-5.4 oz 155-160cc
Rear Swing arm, travel 3.3 in. 85mm
Front Tire 3.25-19 (4PR) Rib tire, 28psi
Rear Tire 4.00-18 (4 PR) Block tire, 28psi
Brakes
Front Type Disk
Front lining swept area 59.3 sq in 382.9 sq cm
Rear Type Internal expanding shoe
Rear lining swept area 34.2 sq in 220.5 sq cm
Fuel
Tank Capacity 4.5 US gal, 3.7 Imp. gal 17 liter
Reserve Capacity 1.3 US gal, 1.1 Imp. gal 5 liter
Carburetor
Type Piston Valve, Keihin, slide type
Setting mark 7A
Air screw opening 1 3/8 turns
Idle speed 950 rpm
Main jet #105
Idle jet #40
Float height 0.866 in. 26mm
Engine
Type Air-cooled, 4-stroke, O.H.C. engine
Cylinder Arrangement 4-cylinder in line
Bore and Stroke 2.402x2.480 in. 61x63 mm
Displacement 44.9135 cu in 736 cc
Compression Ratio 9.0:1
Cylinder head compression 170.7 psi 12 kg/cm sq
Maximum Horsepower 67 BHP@8,000 rpm
Maximum Torque 44.12 lb-ft@7,000 rpm 6.1 kg-m@7,000 rpm
Valve train Chain driven overhead camshaft
Oil Capacity 3.7 US qt, 3.1 Imp. qt 3.5 liter
Oil Tank Capacity 2.1 US qt., 1.8 Imp. qt 2 liter
Lubrication System Forced pressure and dry sump
Air filtration Paper element
Valve Timing
Intake Valve Open At 5º before top dead center
Intake Valve Close At 30º after bottom dead center
Exhaust Valve Open At 35º before bottom dead center
Exhaust Valve Close At 5º after top dead center
Valve Tappet Clearance
Intake 0.002in. 0.05mm
Exhaust 0.003in. 0.08mm
Engine weight (Wet) 176.3 lb 80 kg
Drive Train
Clutch Wet, multi-plate
Transmission Type 5-speed, constant mesh
Gear Ratio I 2.500:1
Gear Ratio II 1.708:1
Gear Ratio III 1.333:1
Gear Ratio IV 1.097:1
Gear Ratio V 0.939:1
Primary reduction 1.708:1
Secondary reduction 1.167:1
Final Reduction 2.667:1 (18T x 48T)
Electrical
Type 12v, negative earth
Ignition Coil and contact breaker, spare spark
Starting system Electrical motor and kick pedal
Alternator Three phase A.C. generator 12V/0.21kW@5,000 rpm
Battery Capacity 12V - 14 amp hour
Spark plug type NGK D8ES-L, NDX 24ES
Spark plug gap 0.024 ~ 0.028 in. 0.6 ~ 0.7 mm
Point gap 0.012 ~ 0.016 in. 0.3 ~ 0.4 mm
Headlight Low/high 12V 40W/50W
Tail/stoplight 12V 3/32 CP (SAE Trade No. 1157)
Turn signal bulb 12V 32/32 CP (SAE Trade no. R1034, L1073)
Speedometer bulb 12V 2CP (SAE Trade No. 57)
Tachometer bulb 12V 2CP (SAE Trade No. 57)
Neutral indicator bulb 12V 2CP (SAE Trade No. 57)
Turn signal indicator bulb 12V 2CP (SAE Trade No. 57)
High beam indicator bulb 12V 2CP (SAE Trade No. 57)
Position light 12V 4CP

CB750K5

Model Guide

Planet Blue Metallic Flake Apricot Red

The CB750 K5 was available only in the US market and offered in two Colors, Planet Blue Metallic and Flake Apricot Red with dark green instrument faces. The speedometer was marked in 10mph increments.

Specifications

Item English Metric
Dimensions
Overall length 85.6 in. 2,175 mm
Overall width 34.3 in. 870 mm
Overall height 46.1 in. 1,170 mm
Wheel base 57.3 in 1,455 mm
Seat height 31.9 in. 810 mm
Foot Peg Height 12.2 in. 310 mm
Ground Clearance 5.5 in. 140 mm
Curb weight (dry) 479 lb 218 kg
Weight distribution L/R 271.1/209.5 lb 123/205 kg
Frame & Suspension
Type Double cradle tubular steel
Front
Fork travel 5.6 in. 143mm
Caster Angle 63º
Trail length 3.74 in. 95mm
Oil capacity (dry) 7.5-7.8 oz 220-230 cc
Oil capacity (full) 5.3-5.4 oz 155-160cc
Rear Swing arm, travel 3.3 in. 85mm
Front Tire 3.25-19 (4PR) Rib tire, 28psi
Rear Tire 4.00-18 (4 PR) Block tire, 28psi
Brakes
Front Type Disk
Front lining swept area 59.3 sq in 382.9 sq cm
Rear Type Internal expanding shoe
Rear lining swept area 34.2 sq in 220.5 sq cm
Fuel
Tank Capacity 4.5 US gal, 3.7 Imp. gal 17 liter
Reserve Capacity 1.3 US gal, 1.1 Imp. gal 5 liter
Fuel Type Low-lead gasoline with 91 octane number or higher
Carburetor
Type Four piston valve type, venturi diameter 28mm
Setting mark 7A
Air screw opening 1 turn
Idle speed 950 rpm
Main jet #105
Idle jet #40
Float height 0.866 in. 26mm
Engine
Type Air-cooled, 4-stroke, O.H.C. engine
Cylinder Arrangement 4-cylinder in line
Bore and Stroke 2.402x2.480 in. 61x63 mm
Displacement 44.9135 cu in 736 cc
Compression Ratio 9.0:1
Cylinder head compression 170.7 psi 12 kg/cm sq
Maximum Horsepower 67 BHP@8,000 rpm
Maximum Torque 44.12 lb-ft@7,000 rpm 6.1 kg-m@7,000 rpm
Valve train Chain driven overhead camshaft
Oil Capacity 3.7 US qt, 3.1 Imp. qt 3.5 liter
Oil Tank Capacity 2.1 US qt., 1.8 Imp. qt 2 liter
Lubrication System Forced pressure and dry sump
Air filtration Paper element
Valve Timing
Intake Valve Open At 5º before top dead center
Intake Valve Close At 30º after bottom dead center
Exhaust Valve Open At 35º before bottom dead center
Exhaust Valve Close At 5º after top dead center
Valve Tappet Clearance
Intake 0.002in. 0.05mm
Exhaust 0.003in. 0.08mm
Engine weight (Wet) 176.3 lb 80 kg
Drive Train
Clutch Wet, multi-plate
Transmission Type 5-speed, constant mesh
Gear Ratio I 2.500:1
Gear Ratio II 1.708:1
Gear Ratio III 1.333:1
Gear Ratio IV 1.097:1
Gear Ratio V 0.939:1
Primary reduction 1.708:1
Secondary reduction 1.167:1
Final Reduction 2.667:1 (18T x 48T)
Electrical
Type 12v, negative earth
Ignition Coil and contact breaker, spare spark
Starting system Electrical motor and kick pedal
Alternator Three phase A.C. generator 12V/0.21kW@5,000 rpm
Battery Capacity 12V - 14 amp hour
Spark plug type NGK D8ES-L, NDX 24ES
Spark plug gap 0.024 ~ 0.028 in. 0.6 ~ 0.7 mm
Point gap 0.012 ~ 0.016 in. 0.3 ~ 0.4 mm
Headlight Low/high 12V 40W/50W
Tail/stoplight 12V 3/32 CP (SAE Trade No. 1157)
Turn signal bulb 12V 32/32 CP (SAE Trade no. R1034, L1073)
Speedometer bulb 12V 2CP (SAE Trade No. 57)
Tachometer bulb 12V 2CP (SAE Trade No. 57)
Neutral indicator bulb 12V 2CP (SAE Trade No. 57)
Turn signal indicator bulb 12V 2CP (SAE Trade No. 57)
High beam indicator bulb 12V 2CP (SAE Trade No. 57)
Position light 12V 4CP

CB750K6

Model Guide

Candy Antares Red

The CB750 K6 replaced the K5 in the US, the K4 in Japan and the K2 in the rest of the world. This model was available in one color, Candy Antares Red and featured light green instrument faces.

Engine # Changes
2470427 clutch almost identical to F1: new clutch basket, new clutch cover and chrome cover
2434657-2439607 New gear shift drum, new center shift fork for improved shifting. New gears on countershaft w/bronze bushings, new case

Specifications

Item English Metric
Dimensions
Overall length 85.6 in. 2,175 mm
Overall width 34.3 in. 870 mm
Overall height 46.1 in. 1,170 mm
Wheel base 57.3 in 1,455 mm
Seat height 31.9 in. 810 mm
Foot Peg Height 12.2 in. 310 mm
Ground Clearance 5.5 in. 140 mm
Curb weight (dry) 479 lb 218 kg
Weight distribution L/R 271.1/209.5 lb 123/205 kg
Frame & Suspension
Type Double cradle tubular steel
Front
Fork travel 5.6 in. 143mm
Caster Angle 63º
Trail length 3.74 in. 95mm
Oil capacity (dry) 7.5-7.8 oz 220-230 cc
Oil capacity (full) 5.3-5.4 oz 155-160cc
Rear Swing arm, travel 3.3 in. 85mm
Front Tire 3.25-19 (4PR) Rib tire, 28psi
Rear Tire 4.00-18 (4 PR) Block tire, 28psi
Brakes
Front Type Disk
Front lining swept area 59.3 sq in 382.9 sq cm
Rear Type Internal expanding shoe
Rear lining swept area 34.2 sq in 220.5 sq cm
Fuel
Tank Capacity 4.5 US gal, 3.7 Imp. gal 17 liter
Reserve Capacity 1.3 US gal, 1.1 Imp. gal 5 liter
Fuel Type Low-lead gasoline with 91 octane number or higher
Carburetor
Type Four piston valve type, venturi diameter 28mm
Setting mark 7A
Air screw opening 1 turn
Idle speed 950 rpm
Main jet #105
Idle jet #40
Float height 0.866 in. 26mm
Engine
Type Air-cooled, 4-stroke, O.H.C. engine
Cylinder Arrangement 4-cylinder in line
Bore and Stroke 2.402x2.480 in. 61x63 mm
Displacement 44.9135 cu in 736 cc
Compression Ratio 9.0:1
Cylinder head compression 170.7 psi 12 kg/cm sq
Maximum Horsepower 67 BHP@8,000 rpm
Maximum Torque 44.12 lb-ft@7,000 rpm 6.1 kg-m@7,000 rpm
Valve train Chain driven overhead camshaft
Oil Capacity 3.7 US qt, 3.1 Imp. qt 3.5 liter
Oil Tank Capacity 2.1 US qt., 1.8 Imp. qt 2 liter
Lubrication System Forced pressure and dry sump
Air filtration Paper element
Valve Timing
Intake Valve Open At 5º before top dead center
Intake Valve Close At 30º after bottom dead center
Exhaust Valve Open At 35º before bottom dead center
Exhaust Valve Close At 5º after top dead center
Valve Tappet Clearance
Intake 0.002in. 0.05mm
Exhaust 0.003in. 0.08mm
Engine weight (Wet) 176.3 lb 80 kg
Drive Train
Clutch Wet, multi-plate
Transmission Type 5-speed, constant mesh
Gear Ratio I 2.500:1
Gear Ratio II 1.708:1
Gear Ratio III 1.333:1
Gear Ratio IV 1.097:1
Gear Ratio V 0.939:1
Primary reduction 1.708:1
Secondary reduction 1.167:1
Final Reduction 2.667:1 (18T x 48T)
Electrical
Type 12v, negative earth
Ignition Coil and contact breaker, spare spark
Starting system Electrical motor and kick pedal
Alternator Three phase A.C. generator 12V/0.21kW@5,000 rpm
Battery Capacity 12V - 14 amp hour
Spark plug type NGK D8ES-L, NDX 24ES
Spark plug gap 0.024 ~ 0.028 in. 0.6 ~ 0.7 mm
Point gap 0.012 ~ 0.016 in. 0.3 ~ 0.4 mm
Headlight Low/high 12V 40W/50W
Tail/stoplight 12V 3/32 CP (SAE Trade No. 1157)
Turn signal bulb 12V 32/32 CP (SAE Trade no. R1034, L1073)
Speedometer bulb 12V 2CP (SAE Trade No. 57)
Tachometer bulb 12V 2CP (SAE Trade No. 57)
Neutral indicator bulb 12V 2CP (SAE Trade No. 57)
Turn signal indicator bulb 12V 2CP (SAE Trade No. 57)
High beam indicator bulb 12V 2CP (SAE Trade No. 57)
Position light 12V 4CP

CB750K7

Model Guide

Excel Black Candy Alpha Red

The 1977 CB750K7 was available worldwide in two colors, Candy Alpha Red and Excel Black. The gas tank featured a gold stripe with a white and red pinstripe. The “750 FOUR K” side cover emblem was gold.

Engine # Changes
2700001 Carburetors w/accelerator pump, shorter intake rubbers, new final drive shaft, sprocket w/center bolt, wider chain line (as F2), final drive 15/41, new clutch, new camshaft (as F1), new pistons (as F), compression ratio 9.2/1. New transmission: 4th gear 1.133 i/o 1.087. Final drive gear 50 teeth i/o 56 (as F1), primary drive 1.985 i/o 1.708
2719530 New valve guides
2719997 New cam carriers (same as F2)

Specifications

Item English Metric
Dimensions
Overall length 89.8 in. 2,280 mm
Overall width 34.6 in. 880 mm
Overall height 46.7 in. 1,185 mm
Wheel base 58.9 in 1,495 mm
Seat height 31.9 in. 810 mm
Foot Peg Height 13.0 in. 330 mm
Ground Clearance 5.9 in. 150 mm
Curb weight (dry) 508 lb 231 kg
Frame & Suspension
Type Double cradle tubular steel
Front
Fork travel 5.6 in. 143 mm
Caster Angle 62º
Trail length 4.5 in. 115 mm
Oil capacity (dry) 7.5-7.8 oz 220-230 cc
Oil capacity (full) 5.3-5.4 oz 155-160cc
Rear Swing arm, travel 4.0 in. 101.6 mm
Front Tire 3.25-19 (4PR) Rib tire, 28psi
Rear Tire 4.50-17 (4 PR) Block tire, 32/40 psi
Brakes
Front Type Disk
Front lining swept area 59.3 sq in 382.9 sq cm
Rear Type Internal expanding shoe
Rear lining swept area 34.2 sq in 220.5 sq cm
Fuel
Tank Capacity 5.0 US gal, 4.2 Imp. gal 19 liter
Reserve Capacity 1.1 US gal, 0.9 Imp. gal 4 liter
Fuel Type Low-lead gasoline with 91 octane number or higher
Carburetor
Type Four piston valve type, venturi diameter 28mm
Pilot Screw Opening Fixed by idle limiter (1 1/2 +/- 1/2)
Idle speed 1000 rpm
Engine
Type Air-cooled, 4-stroke, O.H.C. engine
Cylinder Arrangement 4-cylinder in line
Bore and Stroke 2.402x2.480 in. 61x63 mm
Displacement 44.9135 cu in 736 cc
Compression Ratio 9.2:1
Cylinder head compression 170.7 psi 12 kg/cm sq
Maximum Horsepower 67 BHP@8,000 rpm
Maximum Torque 44.12 lb-ft@7,000 rpm 6.1 kg-m@7,000 rpm
Valve train Chain driven overhead camshaft
Oil Capacity 3.7 US qt, 3.1 Imp. qt 3.5 liter
Oil Tank Capacity 2.1 US qt., 1.8 Imp. qt 2 liter
Lubrication System Forced pressure and dry sump
Air filtration Paper element
Valve Timing
Intake Valve Opens: 0 degrees BTDC Closes 40 degrees ATDC
Exhaust Valve Opens: 40 degrees BBDC Closes 0 degrees ATDC
Valve Tappet Clearance
Intake 0.002in. 0.05mm
Exhaust 0.003in. 0.08mm
Engine weight (Wet) 176.3 lb 80 kg
Drive Train
Clutch Wet, multi-plate
Transmission Type 5-speed, constant mesh
Gear Ratio I 2.500:1
Gear Ratio II 1.708:1
Gear Ratio III 1.333:1
Gear Ratio IV 1.133:1
Gear Ratio V 0.939:1
Primary reduction 1.708:1
Secondary reduction 1.167:1
Final Reduction 2.733, (15Tx41T)
Electrical
Type 12v, negative earth
Ignition Coil and contact breaker, spare spark
Ignition Advance “F” mark: 10 degrees BTDC; Max Advance: 35 degrees; RPM from “F” to Max: 1,200-2,500; Dwell angle: 190 +/- 5 degrees
Starting system Electrical motor and kick pedal
Alternator Three phase A.C. generator 12V/0.21kW@5,000 rpm
Battery Capacity 12V - 14 amp hour
Fuse Capacity Main: 15A; Head: 7A; Tail: 5A
Spark plug USA: NGK D8ES-L, ND X24ES Canada: NGK DR8ES-L ND X24ESR
Condenser Capacity 0.20-0.24 mf

CB750K8

Model Guide

Excel Black Candy Alpha Red

The final single overhead cam CB750 was so | May 1977 - May 1978 | 36,000 | Candy Alpha Red, Excel Black | The gas tank stripe was gold with a gold and red pinstripe. The “750 FOUR” side cover emblem was a graphic design. There was a “K” side cover decal and stripe. The seat is contoured in a stepped design. |

Engine # Changes
3000001 New intake and exhaust valves, new valve spring retainers
3021913 New cylinder block w/larger cam chain tunnel

Specifications

Item English Metric
Dimensions
Overall length 89.8 in. 2,280 mm
Overall width 34.6 in 880 mm
Overall height 46.7 in 1,185 mm
Wheel base 58.9 in 1,495 mm
Seat height 31.9 in 810 mm
Foot Peg Height 13.0 in 330 mm
Ground Clearance 5.9 in 150 mm
Curb weight (dry) 508 lb 231 kg
Frame & Suspension
Type Double cradle
Caster Angle 62º
Trail Length 4.5 in, 115 mm
Fork Oil 5.3-5.4 ozs 145-155cc
Front Suspension Telescopic fork travel 5.6 in., 141.5mm
Rear Suspension Swing arm travel 4.0 in., 101.6mm
Front Tire 3.50H-19 (4PR) Rib air pressure 28 psi
Rear Tire 4.50H-17A (4 PR) Block air pressure 32/40 psi
Brakes
Front Disk
Rear Internal expanding shoe
Fuel
Fuel Octane 91+
Tank Capacity 5.1 US gal, 4.3 Imp. gal 19.5 liter
Reserve Capacity 1.1 US gal, 0.9 Imp. gal 4.0 liter
Engine
Type Air-cooled, 4-stroke, O.H.C. engine
Cylinder Arrangement 4-cylinder in line
Bore and Stroke 2.402x2.408 in 61.0x63.0 mm
Displacement 44.9 ci 736 cc
Compression Ratio 9.2:1
Valve train Chain driven over head camshaft
Lubrication System Forced pressure dry sump
Engine Oil 3.7 US qt, 3.1 Imp. qt 3.5 liter
Valves Timing
Intake Opens: 0 degrees BTDC Closes 40 degrees ATDC
Exhaust Opens: 40 degrees BBDC Closes 0 degrees ATDC
Tappet Clearance
Intake 0.002in. 0.05mm
Exhaust 0.003in. 0.08mm
Carburetor
Type Four piston valve type, venturi diameter 28mm (1.102in)
Air Filtration Paper filter
Pilot Screw Opening Fixed by idle limiter (1 1/2 +/- 1/2)
Idle speed 1000 rpm
Transmission
Type 5-speed, constant mesh
Clutch Wet, multi plate type
Primary reduction 1.708
Gear ratio I 2.500
Gear ratio II 1.708
Gear ratio III 1.333
Gear ratio IV 1.133
Final Reduction 2.733 (15Tx41T)
Gear shift pattern Left foot operated return system
Electrical
Ignition Battery and ignition coil
Ignition Advance “F” mark: 10 degrees BTDC; Max Advance: 35 degrees; RPM from “F” to Max: 1,200-2,500; Dwell angle: 190 +/- 5 degrees
Starting system Electrical motor or kick pedal
Alternator Three phase A.C. generator 0.21kW@5,000 rpm
Battery Capacity 12V - 14AH
Fuse Capacity Main: 15A; Head: 7A; Tail: 5A
Spark plug USA: NGK D8EA, ND X24ES-U Canada: NGK DR8ES-L ND X24ESR-U
Condenser Capacity 0.20-0.24 mf