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Honda GXV-120 Engine

General Technical Data

Honda GXV120 Engine Specifications

Engine Model ................. Honda GXV120
Engine Type ................. 4-cycle overhead valve 1-cylinder air-cooled small gasoline engine
Number of Cylinders ................. Single
Displacement, cu.in (cc) ................. 7.2 (118)
Engine Bore, in (mm) ................. 2.36 (60.0)
Engine Stroke, in (mm) ................. 1.65 (42.0)
Rated Engine Power, hp (kW) ................. 4.0 (2.9)
Rated Engine Speed, rpm ................. 3600
Maximum Torque, Nm (ft-lbs) ................. 8.1 (5.92)
Torque Speed, rpm ................. 2700
Compression ................. 8.7:1/8.0:1
Valve Arrangement ................. OHV
PTO Shaft Rotation ................. Counterclockwise (from PTO side)
Lubrication System ................. Forced splash type
Air Cleaner Type ................. Dual dry element
Cooling System ................. Forced air
Ignition System ................. Transistorized magneto
Stopping System ................. Primary circuit ground
Starting System ................. Recoil starter

Fuel System

Fuel System Type ................. Carburetor
Carburetor Type ................. Horizontal, butterfly valve
Governor Type ................. Mechanical centrifugal
Fuel Tank Capacity, qts (L) ................. 1.1 (1.0)
Fuel Type ................. Gasoline (86 or higher)

Dimensions and Weight

Length, in (mm) ................. 14.8 (375)
Width, in (mm) ................. 13.0 (330)
Height, in (mm) ................. 13.2 (335)
Net Weight, lbs (kg) ................. 22.6 (12.5)

Honda GXV120 Maintenance Data

Cylinder Block and Valves

Cylinder Bore Inside Diameter (Maximum), in (mm) ................. 2.3687 (60.165)
Cylinder Compression, psi (kPa) ................. 71-102 (490-695)
Cylinder Head (Max. Out of Flatness), in (mm) ................. 0.004 (0.10)
Intake Valve Clearance, in (mm) ................. 0.006 (0.15)
Exhaust Valve Clearance, in (mm) ................. 0.008 (0.20)

Engine Oil and Filter

Engine Oil Type (Summer) ................. SAE 10W-30, 10W-40
Engine Oil Type (Winter) ................. SAE 5W-30
API Service Classifications ................. SE or SF
Oil Capacity, qts (L) ................. 0.65 (0.60)
Air Filter Element Part Number ................. 17210-ZE6-505

Carburetor Adjustment

Main Jet ................. #65
Idle Fuel ................. 3 turns out
Float Height, in (mm) ................. 0.48-0.60 (12.2-15.2)
Low Idle Speed, rpm ................. 2000±150
High Idle Speed, rpm ................. 3100±150

Ignition System

Spark Plug Type ................. NGK BPR5ES or Denso W16EPR-U
Spark Plug Gap, in (mm) ................. 0.028-0.032 (0.70-0.80)
Module Air Gap, in (mm) ................. 0.008-0.024 (0.20-0.60)
Ignition Timing, deg ................. 25 BTDC
Spark Plug Torque, Nm (ft-lbs) ................. 20 (14)

Service Intervals

Service Air Cleaner Element ................. Every 50 hours
Change Engine Oil ................. Every 100 hours
Check and Adjust Spark Plug ................. Every 100 hours
Check Carburetor Adjustment ................. Every 200 hours
Check and Adjust Valve Clearance ................. Every 300 hours
Clean Fuel Tank and Filter ................. Every 300 hours
Replace Spark Plug ................. Every 300 hours

Honda GXV120 Service Data

Cylinder Block

Cylinder Bore Inside Diameter (Std), in (mm) ................. 2.3622-2.3628 (60.000-60.015)
Cylinder Bore Inside Diameter (Wear Limit), in (mm) ................. 2.3687 (60.165)
Connecting Rod Small End Inside Diameter (Std), in (mm) ................. 0.5120-0.5126 (13.005-13.020)
Connecting Rod Small End Inside Diameter (Wear Limit), in (mm) ................. 0.515 (13.07)
Connecting Rod Big End Inside Diameter (Std), in (mm) ................. 1.0244-1.0249 (26.020-26.033)
Connecting Rod Big End Inside Diameter (Wear Limit), in (mm) ................. 1.026 (26.066)
Connecting Rod Big End Oil Clearance, in (mm) ................. 0.0016-0.0025 (0.040-0.063)
Crank Pin Outside Diameter (Std), in (mm) ................. 1.0224-1.0228 (25.970-25.980)
Crank Pin Outside Diameter (Wear Limit), in (mm) ................. 1.020 (25.92)

Cylinder Head and Valves

Number of Valves ................. 2
Cylinder Head (Max. Out of Flatness), in (mm) ................. 0.004 (0.10)
Intake Valve Clearance, in (mm) ................. 0.005-0.007 (0.13-0.17)
Exhaust Valve Clearance, in (mm) ................. 0.007-0.009 (0.18-0.22)
Intake Valve Stem Outside Diameter (Std), in (mm) ................. 0.2153-0.2157 (5.468-5.480)
Intake Valve Stem Outside Diameter (Wear Limit), in (mm) ................. 0.2094 (5.318)
Exhaust Valve Stem Outside Diameter (Std), in (mm) ................. 0.2136-0.2146 (5.425-5.450)
Exhaust Valve Stem Outside Diameter (Wear Limit), in (mm) ................. 0.2077 (5.275)
Intake Valve Guide Inside Diameter, in (mm) ................. 0.2165-0.2170 (5.500-5.512)
Exhaust Valve Guide Inside Diameter, in (mm) ................. 0.2165-0.2170 (5.500-5.512)
Intake Valve Guide To Stem Clearance, in (mm) ................. 0.0008-0.0017 (0.020-0.044)
Exhaust Valve Guide To Stem Clearance, in (mm) ................. 0.0020-0.0030 (0.050-0.077)
Valve Seat Width (Intake/Exhaust), in (mm) ................. 0.08 (0.32)
Valve Spring Free Length, in (mm) ................. 1.339 (34.00)
Cam Height (Intake), in (mm) ................. 1.091 (27.700)
Cam Height (Exhaust), in (mm) ................. 1.093 (27.750)
Camshaft Outside Diameter (Std), in (mm) ................. 0.5498-0.5506 (13.966-13.984)
Camshaft Outside Diameter (Wear Limit), in (mm) ................. 0.5479 (13.916)

Piston and Piston Rings

Piston Pin Bore Inside Diameter (Std), in (mm) ................. 0.5119-0.5121 (13.002-13.008)
Piston Pin Bore Inside Diameter (Wear Limit), in (mm) ................. 0.5137 (13.048)
Piston Skirt Outside Diameter, in (mm) ................. 2.3608-2.3616 (59.965-59.985)
Piston to Cylinder Bore Clearance, in (mm) ................. 0.0006-0.0020 (0.015-0.050)
Piston Pin Outside Diameter (Std), in (mm) ................. 0.5116-0.5118 (12.994-13.000)
Piston Pin Outside Diameter (Wear Limit), in (mm) ................. 0.5100 (12.954)
Top Compression Ring Width, in (mm) ................. 0.059 (1.50)
Second Compression Ring Width, in (mm) ................. 0.059 (1.50)
Oil Ring Width, in (mm) ................. 0.098 (2.50)
Top Compression Ring to Groove Side Clearance, in (mm) ................. 0.0006-0.0018 (0.015-0.045)
Second Compression Ring to Groove Side Clearance, in (mm) ................. 0.0006-0.0018 (0.015-0.045)
Oil Ring to Groove Side Clearance, in (mm) ................. 0.0006-0.0018 (0.015-0.045)
Top Compression Ring End Gap, in (mm) ................. 0.008-0.016 (0.20-0.40)
Second Compression Ring End Gap, in (mm) ................. 0.008-0.016 (0.20-0.40)
Oil Ring End Gap, in (mm) ................. 0.006-0.014 (0.15-0.35)
Ring End Gap (Wear Limit), in (mm) ................. 0.04 (1.00)

Honda GXV120 Tightening Torque Specs

Oil Pan Bolt (M6x1.0) ................. 10-14 Nm (7.2-10.1 ft-lb)
Cylinder Head Cover Bolt (M6x1.0) ................. 8-12 Nm (5.8-8.7 ft-lb)
Cylinder Head Stud (M8x1.25x45) ................. 22-26 Nm (15.9-18.8 ft-lb)
Oil Drain Plug Bolt (M10x1.25) ................. 15-20 Nm (10.8-14.5 ft-lb)
Connecting Rod Bolt (M7x1.0) ................. 10-14 Nm (7.2-10.1 ft-lb)
Flywheel Nut (M14x1.5) ................. 70-80 Nm (50.6-57.9 ft-lb)
Muffler Bolt (M6x1.0) ................. 8-12 Nm (5.8-8.7 ft-lb)
Rocker Arm Pivot Bolt (M8x1.25) ................. 22-26 Nm (15.9-18.8 ft-lb)
Air Cleaner Case Bolt (M6x1.0) ................. 7-10 Nm (5.1-7.2 ft-lb)
Governor Arm Nut (M6x1.0) ................. 8-11 Nm (5.8-8 ft-lb)
Spark Plug (M14x1.25) ................. 20 Nm (14 ft-lb)