Kawasaki FH721D Engine

General Technical Data

Kawasaki FH721D Engine Specifications

Engine Model .............. Kawasaki FH721D
Engine Type .............. 4-cycle horisontal shaft OHV air cooled gasoline engine
Number of Cylinder .............. 2
Cylinder Layout .............. 90 deg, V-Twin
Piston Displacement, cc (cu.in) .............. 675 (41.2)
Cylinder Bore, mm (in) .............. 75.2 (2.96)
Piston Stroke, mm (in) .............. 76.0 (2.99)
Engine Power, Hp (kW) .............. 25.0 (18.6)
Rated Engine Speed, rpm .............. 3600
Maximum Torque, Nm (ft-lb) .............. 56 (41.3)
Torque Speed, rpm .............. 2400
Compression Ratio .............. 8.1:1
Direction of Rotation .............. Counterclockwise (PTO Shaft)
Lubricating System .............. Full pressure with spin-on oil filter
Oil Filter Type .............. Cartridge type full flow filter
Air Cleaner Type .............. Dual stage element, dry type
Cooling System .............. Forced air cooling by fan
Ignition System .............. Flywheel magneto transistor type
Starting System .............. Electric starter
Electrical System Rating, Volts .............. 12

Fuel System

Fuel System .............. Carburetor
Carburetor Type .............. Float with fixed main jet, twin barrel
Fuel Pump Type .............. Diaphragm type pulse pump
Governor Type .............. Mechanical
Fuel Type .............. Gasoline (86 or higher)

Dimensions and Weight

Overall Length, mm (in) .............. 442 (17.4)
Overall Width, mm (in) .............. 430 (16.9)
Overall Height, mm (in) .............. 491 (19.3)
Dry weight, kg (lbs) .............. 44.5 (98.1)

Kawasaki FH721D Maintenance Data

Cylinder Block and Valves

Cylinder Inside Diameter (Max), mm (in) .............. 75.28 (2.964)
Cylinder Compression, kPa (psi) .............. 390 (57)
Cylinder Head Warp, mm (in) .............. 0.05 (0.002)
Intake Valve Clearance, mm (in) .............. 0.10-0.15 (0.004-0.006)
Exhaust Valve Clearance, mm (in) .............. 0.10-0.15 (0.004-0.006)

Engine Oil and Filters

Engine Oil Type .............. SAE 10W-30, 10W-40, SAE 5W-20
Oil Classification .............. SF, SG, SH, SJ
Oil Capacity (w/o Filter), L (qts) .............. 1.5 (1.6)
Oil Capacity (with New Filter), L (qts) .............. 1.6 (1.7)
Oil Filter Part Number .............. 49065-7010
Air Filter Element Part Number .............. 11013-7023
Air Filter Pre-Cleaner Part Number .............. 11013-7022

Ignition System

Spark Plug Type .............. NGK BPR4ES
Coil Air Gap, mm (in) .............. 0.20-0.40 (0.0079-0.0158)
Spark Spark Plug Gap, mm (in) .............. 0.75 (0.029)
Spark Plug Torque, Nm .............. 22 (16.2)

Carburetor Adjustments

Model .............. Nikki 621266
Throttle Bore Diameter, mm (in) .............. 26 (1.02)
Venturi Diameter, mm (in) .............. 21 (0.83)
Main Jet .............. #108
Pilot Jet .............. #56
Main Air Jet .............. 1.4
Pilot Air Jet .............. 1.14
Pilot Screw Setting .............. 1-1/4 turn out
Low Idle Speed, rpm .............. 1550±100
High Idle Speed, rpm .............. 3600±100

Service Intervals

Check Engine Oil Level .............. Every 10 hours
Service Air Filter Pre-Cleaner .............. Every 25 hours
Service Air Filter Element .............. Every 100 hours
Change Engine Oil .............. Every 100 hours
Clean and Adjust Spark Plug .............. Every 100 hours
Replace Engine Oil Filter .............. Every 200 hours
Replace Air Filter Element .............. Every 200 hours
Check Carburetor Adjustment .............. Every 300 hours
Check and Adjust Idle Speed .............. Every 300 hours
Check and Adjust Valve Clearance .............. Every 300 hours
Clean Combustion Chamber .............. Every 300 hours
Replace Spark Plug .............. Every 300 hours
Clean Fuel Line .............. Every 300 hours

Kawasaki FH721D Service Specifications

Cylinder Block

Cylinder Inside Diameter (Max), mm (in) .............. 75.28 (2.964)
Cylinder Bore Diameter (Std), 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)
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)
Connecting Rod Small End Inside Diameter, mm (in) .............. 16.05 (0.632)
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)

Cylinder Head and Valves

Cylinder Head Warp, mm (in) .............. 0.05 (0.002)
Valve Clearance, mm (in) .............. 0.10-0.15 (0.004-0.006)
Valve Seating Surface Angle, 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, mm (in) .............. 6.00-6.012 (0.2362-0.2367)
Valve Head Thickness, mm (in) .............. 0.35 (0.014)
Valve Stem Runout, 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, mm (in) .............. 6.08 (0.239)
Valve Spring Free Length, mm (in) .............. 31.0 (1.22)
Rocker Arm Push Rod Run Out, mm (in) .............. 0.5 (0.02)
Cam Lobe Height, mm (in) .............. 29.621 (1.166)

Piston and Piston Rings

Piston Diameter, mm (in) .............. 74.99 (2.952)
Piston Pin Outside Diameter, mm (in) .............. 15.96 (0.628)
Piston Pin Hole Inside Diameter, mm (in) .............. 16.08 (0.633)
Top Ring Groove Clearance, mm (in) .............. 0.18 (0.007)
Second Ring Groove Clearance, mm (in) .............. 0.16 (0.006)
Piston Ring Width, 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)

Tightening Torque Specs

Cylinder Head Bolts .............. 28 Nm (21 ft-lb)
Valve Clearance Lock Screws .............. 6.9 Nm (5.1 ft-lb)
Flywheel Bolt .............. 56 Nm (41 ft-lb)
Crankcase Cover Bolts .............. 25 Nm (19 ft-lb)
Oil Pump Cover Plate Bolts .............. 5.9 Nm (4.4 ft-lb)
Connecting Rod Big End Bolts .............. 9.8 Nm (7.7 ft-lb)
Rocker Arm Bolts .............. 28 Nm (20 ft-lb)
Rocker Cover Mounting Bolts .............. 6.9 Nm (5.1 ft-lb)
Exhaust Pipe Flange Nuts .............. 15 Nm (11 ft-lb)
Spark Plugs .............. 22 Nm (16 ft-lb)
Governor Arm Clamp Nut .............. 7.8 Nm (5.8 ft-lb)
Ignition Coil Bolts .............. 5.9 Nm (4.4 ft-lb)
Starter Motor Mounting Bolts .............. 15 Nm (11 ft-lb)
Intake Manifold Mounting Bolts .............. 5.9 Nm (4.4 ft-lb)