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Kawasaki FH641V Engine

General Technical Data

Kawasaki FH641V Engine Specifications

Engine Model ..................... Kawasaki FH641V
Engine Type ..................... 4-Stroke, Forced Air-cooled, Vertical Shaft, OHV Gasoline
Gasoline Engine
Number of Cylinder ..................... 2
Cylinder Layout ..................... 90 deg V-Twin
Piston Displacement, cc (cu.in) ..................... 675 (41.2)
Engine Bore, mm (in) ..................... 75.2 (2.96)
Engine Stroke, mm (in) ..................... 76.0 (2.99)
Engine Power, Hp (kW) ..................... 21.0 (15.7)
Rated Engine Speed, rpm ..................... 3600
Maximum Torque, Nm (ft-lb) ..................... 52 (38.4)
Torque Speed, rpm ..................... 2400
Compression Ratio ..................... 8.1:1
Direction of Rotation ..................... Counterclockwise facing the PTO Shaft
Lubricating System Type ..................... Pressure feed by positive displacement pump
Oil Filter ..................... Cartridge type full flow filter
Ignition System Type ..................... Transistorized Flywheel Magneto

Fuel System

Fuel System Type ..................... Carburetor
Carburetor Type ..................... Twin barrel, Float type with fixed main jet
Fuel Pump ..................... Diaphragm Type Pulse Pump
Fuel ..................... Unleaded gasoline
Governor ..................... Mechanical
Air Cleaner ..................... Dual stage element, dry type

Electrical System

Electrical System Rating, Volts ..................... 12
Charging Coil ..................... 12V-13 amps with regulator
Starting System ..................... Bendix type starter
Electric Starter ..................... 12V-0.6 kW
Recommended Battery ..................... 12V-200CCA

Dimensions

Length, mm (in) ..................... 458 (18.0)
Width, mm (in) ..................... 430 (17.0)
Height, mm (in) ..................... 461 (18.2)
Dry weight, kg (lbs) ..................... 40.0 (88)

Kawasaki FH641V Maintenance Data

Cylinder Block and Valves

Cylinder Bore (Maximum), mm (in) ..................... 75.26 (2.9747)
Cylinder Compression (Minimum), kPa ..................... 390
Intake Valve Clearance (Cold), mm (in) ..................... 0.10-0.15 (0.0040-0.0059)
Exhaust Valve Clearance (Cold), mm (in) ..................... 0.10-0.15 (0.0040-0.0059)

Engine Oil and Filter

Engine Oil Type ..................... SAE 10W-30/10W-40, SAE 5W-20
Oil Classification ..................... SF, SG, SH, SJ or SL
Oil Capacity (w/o Filter), L (qts) ..................... 1.5 (1.6)
Oil Capacity (with New Filter), L (qts) ..................... 1.7 (1.8)
Oil Filter Part Number ..................... 49065-7010
Air Filter Part Number ..................... 11013-7027

Carburetor Specifications

Carburetor Model ..................... Nikki 621266
Throttle Bore Diameter, mm (in) ..................... 26.0 (1.02)
Venturi Diameter, mm (in) ..................... 21.0 (0.83)
Main Jet ..................... #116
Pilot Jet ..................... #43.8
Main Air Jet ..................... 1.4
Pilot Air Jet ..................... 0.8
Pilot Air Screw Turns Out ..................... 1-3/8
Float Level ..................... Float parallel to carburetor body
Low Idle Speed, rpm ..................... 1550 ± 100
High Idle Speed, rpm ..................... 3600 ± 100

Ignition System

Plug Type ..................... Champion RCJ8Y or NGK BPMR6A
Plug Gap, mm (in) ..................... 0.75 (0.0296)
Ignition Coil Air Gap, mm (in) ..................... 0.20-0.40 (0.0079-0.0158)

Service Intervals

Change Engine Oil ..................... Every 100 Hours
Change Oil Filter ..................... Every 200 Hours
Clean and Re-gap Spark Plug ..................... Every 100 Hours
Replace Spark Plug ..................... Every 300 Hours
Clean Air Cleaner Paper Element ..................... Every 50 Hours
Replace Air Cleaner Paper Element ..................... Every 200 Hours
Check Carburetor Adjustment ..................... Every 100 Hours
Check and Adjust Valve Clearance ..................... Every 300 Hours

Kawasaki FH641V Service Specifications

Cylinder Head and Valves

Cylinder head warp, mm (in) ..................... 0.05 (0.002)
Valve clearance (Intake, Exhaust), mm (in) ..................... 0.10-0.15 (0.0040-0.0059)
Valve seating surface angle (Intake, Exhaust), deg ..................... 45
Valve seating surface width (Intake), mm (in) ..................... 0.8-1.4 (0.03-0.06)
Valve seating surface width (Exhaust), mm (in) ..................... 1.1-1.6 (0.04-0.06)
Valve guide inside diameter (Intake, Exhaust), mm (in) ..................... 6.00-6.012 (0.2362-0.2367)
Valve head thickness (Intake, Exhaust), mm (in) ..................... 0.35 (0.014)
Valve stem runout (Intake, Exhaust), mm (in) ..................... 0.05 (0.002)
Valve stem diameter (Intake), mm (in) ..................... 5.95 (0.0234)
Valve stem diameter (Exhaust), mm (in) ..................... 5.93 (0.0233)
Valve guide inside diameter (Intake, Exhaust), mm (in) ..................... 6.08 (0.239)
Valve spring free length (Intake, Exhaust), mm (in) ..................... 31.0 (1.22)
Rocker arm push rod run out (Intake, Exhaust), mm (in) ..................... 0.5 (0.02)

Cylinder and Pistons

Cylinder compression, kPa (psi) ..................... 390 (57)
Cylinder inside diameter (Standard), mm (in) ..................... 75.28 (2.964)
Cylinder inside diameter (0.50 Oversize), mm (in) ..................... 75.78 (2.983)
Cylinder bore diameter (Standard), mm (in) ..................... 75.18-75.20 (2.960-2.961)
Cylinder bore diameter (0.50 Oversize), mm (in) ..................... 75.68-75.70 (2.979-2.980)
Cylinder bore out round, mm (in) ..................... 0.056 (0.0022)
Piston diameter, mm (in) ..................... 74.99 (2.952)
Piston top ring/groove clearance, mm (in) ..................... 0.18 (0.007)
Piston second ring/groove clearance, mm (in) ..................... 0.16 (0.006)
Piston ring thickness, mm (in) ..................... 1.40 (0.055)
Piston top ring end gap, mm (in) ..................... 0.65 (0.026)
Piston second ring end gap, mm (in) ..................... 0.78 (0.031)
Piston oil ring end gap, mm (in) ..................... 1.05 (0.041)
Piston pin outside diameter, mm (in) ..................... 15.96 (0.628)
Piston pin hole inside diameter, mm (in) ..................... 16.08 (0.633)
Connecting rod small end inside diameter, mm (in) ..................... 16.05 (0.632)
Cam lobe height, mm (in) ..................... 29.621 (1.166)

Crankshaft and Connecting Rod

Connecting rod big end width, mm (in) ..................... 19.90 (0.783)
Crankpin width, mm (in) ..................... 43.1 (1.697)
Connecting rod big end inside diameter, mm (in) ..................... 38.055 (1.498)
Crankpin outside diameter, mm (in) ..................... 37.94 (1.494)
Crankshaft journal diameter, mm (in) ..................... 39.896 (1.571)
Crankshaft journal bearing inside diameter, mm (in) ..................... 40.15 (1.581)

Lubricating System

Oil pressure, kPa (psi) ..................... 241-310 (35-45)
Oil pressure switch, kPa (psi) ..................... 98 (14.2)
Oil filter by-pass valve openning pressure, kPa (psi) ..................... 78.5-117.5 (11.4-17.1)
Oil pump inner and outer rotor clearance, mm (in) ..................... 0.2 (0.008)
Oil pump outer rotor outside diameter, mm (in) ..................... 40.470 (1.5933)
Oil pump housing inside diameter, mm (in) ..................... 40.801 (1.6063)
Oil pump housing depth, mm (in) ..................... 10.230 (0.4028)
Oil pump shaft outside diameter, mm (in) ..................... 10.923 (0.4300)
Oil pump shaft bearing inside diameter, mm (in) ..................... 11.072 (0.4359)
Relief valve spring free length, mm (in) ..................... 19.50 (0.77)

Kawasaki FH641V Tightening Torque Specs

Cylinder Head Bolts ..................... 25 Nm (19 ft-lb)
Valve Clearance Lock Screws ..................... 6.9 Nm (61 in-lb)
Connecting Rod Big End ..................... 5.9 Nm (52 in-lb)
Rocker Arm Bolts ..................... 28 Nm (20 ft-lb)
Rocker Cover Mounting Bolts ..................... 5.9 Nm (52 in-lb)
Exhaust Pipe Flange Nuts ..................... 15 Nm (11 ft-lb)
Spark Plugs ..................... 22 Nm (16 ft-lb)
Drain Screw (Carburetor) ..................... 1.3 Nm (11 in-lb)
Governor Arm Clamp Nut ..................... 7.8 Nm (69 in-lb)
Intake Manifold Mounting Bolts ..................... 5.9 Nm (52 in-lb)
Cleaner Body Mounting Screws ..................... 3.4 Nm (30 in-lb)
Plug Bolt (Engine-shroud) ..................... 5.9 Nm (52 in-lb)
Plug Screw (Engine-shroud) ..................... 3.4 Nm (30 in-lb)
Choke Valve Screw ..................... 0.7 Nm (6 in-lb)
Throttle Valve Screws ..................... 1.0 Nm (9 in-lb)