CB750 K8: 1978

Production Dates May 1977 through May 1978
Production Numbers 36,000
US Serial Numbers Frame: 3000001 – 3062980
Engine: 2800001 – 2862980
Canada Serial Numbers Frame: 3001934 – 3061938
Engine: 2801946 – 2861935
Colors Candy Alpha Red, Excel Black
Features 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.

Item English Metric
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
Front Suspension Telescopic fork, travel 5.6 in., 141.5mm
Rear Suspension Swing arm, travel 4.0 in., 101.6mm
Front Tire Size, Type 3.50H-19 (4PR) Rib, tire air pressure 2.0 kg/cm2, 28 psi
Rear Tire Size, Type 4.50H-17A (4 PR) Block, tire air pressure 2.25/2.8 kg/cm2, 32/40 psi
Front Brake Disk brake
Rear Brake Internal expanding shoe
Fuel Capacity 5.1 US gal, 4.3 Imp. gal 19.5 liter
Fuel Reserve Capacity 1.1 US gal, 0.9 Imp. gal 4.0 liter
Caster Angle 62º
Trail Length 4.5 in. 115 mm
Front fork oil capacity (refill) 5.3-5.4 ozs 145-155cc

Item English Metric
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 cu in 736 cc
Compression Ratio 9.2:1
Carburetor Four piston valve type, venturi diameter 28mm (1.102in)
Valve train Chain driven over head camshaft
Oil Capacity 3.7 US qt, 3.1 Imp. pt 3.5 liter
Lubrication System Forced pressure and dry sump
Fuel Required Low-lead gasoline with 91 octane number or higher
Air Filtration Paper filter
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
Pilot Screw Opening Fixed by idle limiter (1 1/2 +/- 1/2)
Idle speed 1000 rpm

Gear ratio V
Drive Train
Clutch Wet, multi plate type
Transmission 5-speed, constant mesh
Primary reduction1.708
Gear ratio I 2.500
Gear ratio II 1.708
Gear ratio III 1.333
Gear ratio IV 1.133
Final Reduction 2.733, drive sprocket 15T, driven sprocket 41T
Gear shift pattern Left foot operated return system

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
Condenser Capacity 0.20-0.24 mf