Kawasaki FH381V KAI

The Kawasaki FH381V is a 0.43 l (431 cc, 26.3 cu-in) V-twin 90° air-cooled 4-stroke internal combustion small gasoline engine with vertical shaft, manufactured by Kawasaki Heavy Industries LTd., for general-purpose applications. The Kai’s are the newer series engine. The Japanese word “KAI” means evolution, advancement and renewal. The FH381V KAI engine is based on the FH381V motor, but it has some changes such as: redesigned air cleaner and blower housings, new air filter options, internally vented carburetor, an advanced lubrication system design, and enhancements for optimal startability.

The FH381V KAI has vertical PTO shaft; V-twin 90° design with cast iron cylinder liners and overhead valves (OHV). The engine is equipped with an internally vented carburetor with fuel shut-off solenoid and electronic spark ignition system. The Kawasaki FH381V KAI engine uses a full pressure lubrication system with spin-on oil filter and dual element air cleaner.

The engine has bendix type electric starter, automatic compression release system (ACR) and 12V-13A charging coil with a regulator.

It has a 65 mm (2.56 in) cylinder bore and 65 mm (2.56 in) piston stroke. Compression ratio rating is 8.5:1. The Kawasaki FH381V KAI produced 13.2 PS (9.7 kW; 13.0 HP) at 3,600 rpm and 27.5 Nm (2.8 kg·m; 20.3 ft·lb) at 2,400 rpm of torque.

General information

Engine Specifications
Model	FH381V KAI
Type	4-stroke, OHV, V-twin 90°
Displacement	431 cm 3 (26.3 cu-in)
Max. horsepower	13.2 PS (9.7 KW; 13.0 HP) at 3,600 rpm
Max. torque (crank PTO)	27.5 Nm (2.8 kg·m; 20.3 ft·lb) at 2,400 rpm
Carburetor	Internally vented carburetor
Cooling system	Air-cooling
Ignition system	Electronic spark ignition
Lubricating system	Full pressure with spin-on oil filter
Starting system	Electric starter
Charging system	12 Volt – 13A with regulator
Fuel used	Unleaded gasoline (octane number 86 or higher)
Fuel consumption	245 g/HPh
Cooling system	Pressurized forced circulation type

Tightening torque specs

Tightening torque specs
Cylinder head	25 Nm; 2.2 kg·m; 18.5 ft·lb
Connecting rod	6 Nm; 0.6 kg·m; 4.4 ft·lb
Flywheel	56 Nm; 5.7 kg·m; 41.3 ft·lb
Crankcase cover	25 Nm; 2.2 kg·m; 18.5 ft·lb
Intake manifold	7 Nm; 0.7 kg·m; 5.2 ft·lb
Valve clearance lock nut	7 Nm; 0.7 kg·m; 5.1 ft·lb

Maintenance data

Engine
Maximum speed	3500 ± 100 rpm
Idle speed	1500 ± 100 rpm
Cylinder compression	3.9 kg/cm2 (56 psi) at 500 rpm
Valve clearance
Intake valve	0.10-0.15 mm (0.004-0.006 in)
Exhaust valve	0.10-0.15 mm (0.004-0.006 in)
Oil system
Oil type	4-stroke or an equivalent (SF, SG, SH, or SJ )
Recommended oil	SAE 10W-40, 10W-30, 5W-20
Oil capacity (with filter changed)	1.8 litre (1.9 US.qt.)
Ignition system
Spark plug	CHAMPION: RCJ8Y; NGK: BPMR6A
Spark plug gap	0.75 mm (0.029 in)
Spark plug tightening torque	22 Nm; 2.2 kg·m; 16.2 ft·lb