Kawasaki FD661D

The Kawasaki FD661D is a 0.62 l (617 cc, 37.65 cu-in) V-twin 90° liquid-cooled 4-stroke internal combustion small gasoline motor with horisontal shaft, manufactured by Kawasaki Heavy Industries LTd., for general-purpose applications.

The FD661D has OHV (overhead valve design); cast-iron cylinder liners; float type carburetor with fixed main jet; transistorized fuel pump; full transistor ignition system with fixed timing; mechanical governor and low tone muffler. The Kawasaki FD661D uses a full pressure lubrication system with spin-on oil filter and dual element air cleaner.

The engine was equipped with solenoid shift-type electric starter and 12V-20A charging coil with a regulator.

The Kawasaki FD661D develops 22.3 PS (16.4 kW; 22.0 HP) at 3,600 rpm and 45.7 Nm (4.66 kg·m; 33.73 ft·lb) at 2,400 rpm of torque. It has a 76.0 mm (2.99 in) cylinder bore and 68.0 mm (2.68 in) piston stroke. Compression ratio rating is 10.3:1.

General information

Engine Specifications
Model	FD661D
Type	4-stroke, OHV, V-twin 90°
Displacement	617 cm 3 (37.65 cu-in)
Max. horsepower	22.3 PS (16.4 KW; 22.0 HP) at 3,600 rpm
Max. torque (crank PTO)	45.7 Nm (4.66 kg·m; 33.73 ft·lb) at 2,800 rpm
Carburetor	Float type
Cooling system	Liquid-cooling
Ignition system	Transistorized ignition
Lubricating system	Pressure feed lubrication system
Starting system	Electric starter
Charging system	12 Volt – 20A with regulator
Fuel used	Unleaded gasoline (octane number 86 or higher)
Fuel consumption	230 g/HPh
Cooling system	Pressurized forced circulation type

Dimensions and Weight

	Kawasaki FD661D
Length, mm (in)	556 (21.9)
Width, mm (in)	437 (17.2)
Height, mm (in)	586 (23.0)
Dry weight, kg (lb)	47.2 (104.1)

Cylinder Block and Head

Cylinder block
Compression ratio:		9.0:1
Bore x stroke:		76.0 x 68.0 mm (2.99 x 2.68 in)
Cylinder internal diameter (standard):		76.067 mm (2.9948 in)
Piston skirt outer diameter (standard):		75.875 mm (2.9872 in)
Number of piston rings (compression / oil):		2/1
Connecting rod small end diameter (standard):		17.051 mm (0.6713 in)
Piston pin diameter:		16.975 mm (0.6683 in)
Side clearance:	Top	0.150 mm (0.0059 in)
	Second	0.120 mm (0.0047 in)
Ring end gap:	Top	1.200 mm (0.0472 in)
	Second	1.200 mm (0.0472 in)
Ring width:	Top	1.120 mm (0.0441 in)
	Second	1.120 mm (0.0441 in)
	Oil	1.500 mm (0.0591 in)
Cylinder head
Valve arrangement:		OHV
Valves:		2,(4 valves in total)
Valve steam diameter:	INTAKE	5.945 mm (0.2341 in)
	EXHAUST	5.925 mm (0.2333 in)
Valve spring free length:	INTAKE	29.70 mm (1.1693 in)
	EXHAUST	29.70 mm (1.1693 in)

Tightening torque specs

Tightening torque specs
Cylinder head	21 Nm; 2.1 kg·m; 15.5 ft·lb
Connecting rod	21 Nm; 2.1 kg·m; 15.5 ft·lb
Flywheel	110 Nm; 11.2 kg·m; 81 ft·lb
Crankcase cover	25 Nm; 2.5 kg·m; 18.4 ft·lb
Intake manifold	8 Nm; 8.0 kg·m; 6 ft·lb
Oil drain plug	23 Nm; 2.3 kg·m; 17 ft·lb
Valve clearance lock nut	8.8 Nm; 0.9 kg·m; 6.5 ft·lb

Maintenance data

Engine
Maximum speed	3500 ± 100 rpm
Idle speed	1500 ± 100 rpm
Cylinder compression	12.0 kg/cm2 (170 psi) at 500 rpm
Valve clearance
Intake valve	0.25 mm (0.010 in)
Exhaust valve	0.25 mm (0.010 in)
Oil system
Oil type	4-stroke or an equivalent (SC, SD, SE, SF, SG, or SH)
Recommended oil	SAE 10W-40, 10W-30, 5W-20
Oil capacity (with filter changed)	1.5 L (1.6 US qt)
Ignition system
Spark plug	NGK: BPR5ES
Spark plug gap	0.6-0.7 mm (0.024-0.028 in)
Spark plug tightening torque	15 Nm; 1.5 kg·m; 11 ft·lb