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Kawasaki FD731V Engine

General Technical Data

Kawasaki FD731V Engine Specifications

Engine Model ............... Kawasaki FD731V
Engine Type ............... Liquid-cooled, Vertical shaft, OHV, 4-stroke, V-twin, Gasoline engine
Number of Cylinders ............... 2
Cylinder Liners ............... Cast iron
Displacement, L (cu in) ............... 0.675 (41.2)
Engine Bore, mm (in) ............... 75.2 (2.96)
Engine Stroke, mm (in) ............... 76.0 (2.99)
Maximum Horse Power, hp (kW) ............... 26.0 (19.4)
Rated Engine Speed, rpm ............... 3600
Maximum Torque, Nm (ft-lbs) ............... 57.7 (42.6)
Torque Speed, rpm ............... 2400
Fast Idle Speed, rpm ............... 3550
Slow Idle Speed, rpm ............... 1550
Compression Ratio ............... 8.5:1
Lubrication System ............... Pressure feed by positive displacement pump
Oil Filter ............... Cartridge type full flow
Cooling System ............... Pressurized forced circulation type
Ignition System ............... Solid-state type
Spark Plug ............... NGK BPR2ES
Starting System ............... Shift type electric starter
Charging System ............... 12V 12/20A with regulator

Fuel System

Fuel System ............... Carburetor
Carburetor ............... Float type, fixed main jet
Fuel Pump ............... Diaphragm type pulse pump
Fuel ............... Unleaded gasoline (octane number 86 or higher)
Governor ............... Flyweight all speed governor
Air Cleaner ............... Dual stage element, dry type

Dimensions

Length, mm (in) ............... 432 (17.0)
Width, mm (in) ............... 435 (17.1)
Height, mm (in) ............... 555 (21.9)
Net weight, kg (lbs) ............... 45.0 (99.0)

Kawasaki FD731V Maintenance Data

Cylinder Block and Valves

Cylinder Bore (Maximum), mm (in) ............... 75.3 (2.9763)
Cylinder Compression (Minimum), kPa ............... 682
Intake Valve Clearance (Cold), mm (in) ............... 0.15 (0.0059)
Exhaust Valve Clearance (Cold), mm (in) ............... 0.15 (0.0059)

Engine Oil and Filter

Engine Oil Type ............... SAE 10W-30/10W-40, SAE 5W-20
Oil Classification ............... SF, SG, SH or SJ
Oil Capacity (w/o Filter), L (qts) ............... 2.0 (2.2)
Oil Capacity (with New Filter), L (qts) ............... 2.3 (2.5)
Oil Filter Part Number ............... 49065-2071
Air Filter Part Number ............... 11013-7045

Kawasaki FD731V Caburetor Specifications

Caburetor Model ............... Mikuni BW26
Throttle Bore Diameter, mm (in) ............... 26.0 (1.02)
Venturi Diameter, mm (in) ............... 21.0 (0.83)
Main Jet (R/L) ............... #120 / #115
Pilot Jet (R/L) ............... #50 / #46.3
Main Air Jet ............... 1.7
Pilot Air Jet ............... 1.2
Pilot Air Screw Turns Out (L/R) 2-7/8 / 3-11/16
Float Level ............... Float parallel to carburetor body
Low Idle Speed, rpm ............... 1550 ± 100
High Idle Speed, rpm ............... 3600 ± 100

Ignition System

Plug Type ............... NGK BPR2ES
Plug Gap, mm (in) ............... 0.75 (0.0296)
Ignition Coil Air Gap, mm (in) ............... 0.25-0.40 (0.0099-0.0158)
Ring End Gap (Maximum), mm (in) ............... 0.7 (0.0277)

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 100 Hours
Replace Air Cleaner Paper Element ............... Every 300 Hours
Check Carburetor Adjustment ............... Every 100 Hours
Check and Adjust Valve Clearance ............... Every 300 Hours
Change Coolant ............... Every 400 Hours

Kawasaki FD731V Service Specifications

Cylinder Block

Cylinder head warp, mm (in) ............... 0.03 (0.001)
Cylinder inside diameter, mm (in) ............... 75.30 (2.965)
Cylinder bore out round, mm (in) ............... 0.056 (0.0022)
Cylinder bore diameter (Standard cylinder), mm (in) ............... 75.18-75.2 (2.598-2.9606)
Rocker arm push rod runout (Inlet, Exhaust), mm (in) ............... 0.5 (0.02)
Rocker arm collar outside diameter (Inlet, Exhaust), mm (in) ............... 10.914 (0.4297)
Rocker arm bearing inside diameter (Inlet, Exhaust), mm (in) ............... 11.132 (0.4382)

Valves

Valve head thickness (Inlet, Exhaust), mm (in) ............... 0.35 (0.014)
Valve stem bend (Inlet, Exhaust), mm (in) ............... 0.05 (0.002)
Valve stem diameter (Inlet, Exhaust), mm (in) ............... 6.94 (0.2730)
Valve guide inside diameter (Inlet, Exhaust), mm (in) ............... 7.08 (0.279)
Valve spring free length (Inlet, Exhaust), mm (in) ............... 32.9 (1.30)
Valve clearance (Inlet, Exhaust), mm (in) ............... 0.15 (0.006)
Valve seating surface angle (Inlet, Exhaust), degrees ............... 45
Valve seating surface width (Inlet), mm (in) ............... 0.8-1.4 (0.031-0.055)
Valve seating surface width (Exhaust), mm (in) ............... 1.1-1.6 (0.43-0.063)
Valves guide inside diameter (Inlet, Exhaust), mm (in) ............... 7.000-7.015 (0.2756-0.2762)

Piston and Piston Rings

Top ring groove clearance, mm (in) ............... 0.16 (0.0063)
Second ring groove clearance, mm (in) ............... 0.15 (0.0059)
Top ring thickness, mm (in) ............... 1.40 (0.055)
Second ring thickness, mm (in) ............... 1.40 (0.055)
Piston ring end gap (Top and second ring), mm (in) ............... 0.7 (0.03)
Piston ring end gap (Oil ring), mm (in) ............... 1.0 (0.04)
Piston pin outside diameter, mm (in) ............... 15.96 (0.628)
Piston pin hole inside diameter, mm (in) ............... 16.09 (0.6335)
Connecting rod small end inside diameter, mm (in) ............... 16.06 (0.6323)
Piston outside diameter, mm (in) ............... 74.98 (2.952)

Camshaft and Tappet

Cam Lobe Height (Inlet, Exhaust), mm (in) ............... 41.45 (1.6319)
Camshaft Journal Diameter (PTO Side), mm (in) ............... 15.99 (0.6295)
Camshaft Journal Diameter (Flywheel Side), mm (in) ............... 15.99 (0.6295)
Camshaft Bearing Inside Diameter (Crankcase), mm (in) ............... 16.08 (0.6331)
Camshaft Bearing Inside Diameter (Crankcase Cover), mm (in) ............... 16.08 (0.6331)

Crankshaft and Connecting Rod

Connecting Rod Bend, mm (in) ............... 0.2/100 (0.008/3.94)
Connecting Rod Twist, mm (in) ............... 0.2/100 (0.008/3.94)
Connecting Rod Big End Width, mm (in) ............... 20.2 (0.795)
Crankpin Width, mm (in) ............... 45.0 (1.772)
Connecting Rod Big End Inside Diameter, mm (in) ............... 40.05 (1.577)
Crankpin Outside Diameter, mm (in) ............... 39.95 (1.573)
Crankshaft Runout TIR, mm (in) ............... 0.05 (0.002)
Crankshaft Journal Diameter (PTO Side), mm (in) ............... 39.90 (1.571)
Crankshaft Journal Diameter (Flywheel Side), mm (in) ............... 39.90 (1.571)
PTO Shaft Bearing Inside Diameter (Crankcase Cover), mm (in) ............... 40.04 (1.576)
Crankshaft Journal Bearing Inside Diameter (Crankcase), mm (in) ............... 40.01 (1.575)

Kawasaki FD731V Tightening Torque Specs

Cylinder Head, Nm (ft-lbs) ............... 32 (23.6)
Connecting Rod, Nm (ft-lbs) ............... 9.8 (7.2)
Rocker Arm Bracket Mounting Bolts, Nm (ft-lbs) ............... 22 (16.3)
Flywheel, Nm (ft-lbs) ............... 56 (41.1)
Crankcase Cover, Nm (ft-lbs) ............... 21 (15.5)
Intake Manifold, Nm (ft-lbs) ............... 6 (4.4)
Carburetor and Inlet Pipe Mounting Bolts and Nuts, Nm (ft-lbs) ............... 12 (8.9)
Oil Drain Plug, Nm (ft-lbs) ............... 7 (5.2)
Spark Plug, Nm (ft-lbs) ............... 25 (18.6)
Valve Clearance Lock Nut, Nm (ft-lbs) ............... 11 (8.1)
Water Pump Cover Mounting Bolts (M6), Nm (ft-lbs) ............... 10 (7.9)