Honda GX120 UT2/T2

Honda GX120 UT2/T2The Honda GX120 UT2/T2 is a 118 cc (7.2 cu·in) natural aspirated single-cylinder four-stroke air-cooled internal combustion small gasoline engine with horizontal shaft, manufactured by Honda Motor Company for general-purpose applications.

The GX120 UT2/T2 engine produced 3.5 PS (2.6 kW; 3.5 HP) at 3,600 rpm of maximum horsepower and 7.3 N·m (0.7 kg·m, 5.4 ft·lb) at 2,500 rpm of maximum torque.

The Honda GX120 UT2/T2 features:

  • Overhead valve (OHV) design
  • C.D.I. (Capacitor Discharge Ignition)
  • Horizontal carburetor with butterfly valve
  • Centrifugal governor
  • Forced splash lubrication system
  • Forced air cooling system
  • Recoil starter

General information

Engine Specifications
Engine modelGX120 UT2/T2
Engine type4-stroke, OHV, single-cylinder
Displacement118 cm3, (7.2 cu·in)
Max. horsepower3.5 PS (2.6 kW; 3.5 HP) at 3,600 rpm
Max. torque7.3 N·m (0.7 kg·m, 5.4 ft·lb) at 2,500 rpm
Cooling systemForced air
Lubricating systemForced splash
Ignition systemC.D.I. (Capacitor Discharge Ignition) type magneto ignition
Fuel systemHorizontal type carburetor with butterfly valve
Fuel consumption1.0 L (0.26 US gal, 0.22 Imp gal) / h
Fuel tank capacity2.0 L (0.53 US. gal. 0.44 Imp. gal.)
Fuel usedUnleaded gasoline (octane number 86 or higher)
Starting systemRecoil starter
Stoping systemIgnition primary circuit ground
PTO shaft rotationCounterclockwise (from PTO shaft side)
Dimensions (L x W X H)Type H: 370 x 346 x 329 mm (14.6 x 13.6 x 13 in)
Dry weight15.5 kg (34.2 lbs)

Cylinder Block and Head

Cylinder block
Compression ratio:8.5:1
Cylinder bore:60.0 mm (2.36 in)
Piston stroke:42.0 mm (1.65 in)
Cylinder internal diameter (standard):60.000-60.015 mm (2.3622-2.3628 in)
Piston skirt outer diameter (standard):59.965-59.985 mm (2.3608-2.3616 in)
Number of piston rings (compression / oil):2 / 1
Connecting rod big end diameter (standard):26.020-26.033 mm (1.0244-1.0249 in)
Connecting rod small end diameter (standard):13.005 -13.020 mm (0.512-0.5126 in)
Piston pin diameter:12.994-13.000 mm (0.5116-0.5118 in)
First ring side clearance:0.035-0.070 mm (0.0014-0.0028 in)
Second ring side clearance:0.045-0.080 mm (0.0018-0.0031 in)
First ring end gap:0.200-0.350 mm (0.0079-0.0138 in)
Second ring end gap:0.350-0.500 mm (0.0138-0.0197 in)
Oil ring end gap:0.200-0.700 mm (0.0079-0.0276 in)
First ring width:0.950-0.970 mm (0.0374-0.0382 in)
Second ring width:0.940-0.960 mm (0.037-0.0378 in)
Crankpin journal diameter:25.970-25.980 mm (1.0224-1.0228 in)
Crankshaft center distance:21 mm (0.825 in)
Cylinder head
Valve arrangement:OHV, gear driven
Intake valve steam diametr:5.468-5.480 mm (0.2153-0.2157 in)
Exhaust valve steam diametr:5.425 -5.440 mm (0.2136-0.2142 in)
Intake valve spring free length:30.5 mm (1.2008 in)
Exhaust valve spring free length:30.5 mm (1.2008 in)
Intake camshaft lobe height:27.500-27.900 mm (1.0827-1.0984 in)
Exhaust camshaft lobe height:27.547-27.947 mm (1.0845-1.1003 in)
Camshaft journal diameter :13.966 -13.984 mm (0.5498-0.5506 in)

Tightening torque

Tightening torque specs
Connecting rod bolt12 Nm; 1.2 kg·m; 9 ft·lb
Cylinder head bolt24 Nm; 2.4 kg·m; 17 ft·lb
Flywheel nut75 Nm; 7.5 kg·m; 54 ft·lb
Rocker arm pivot adjusting nut10 Nm; 1.0 kg·m; 7 ft·lb
Rocker arm pivot bolt24 Nm; 2.4 kg·m; 17 ft·lb
Crankcase cover bolt12 Nm; 1.2 kg·m; 9 ft·lb
Oil level switch joint nut10 Nm; 1.0 kg·m; 7 ft·lb

Service Data

Maximum speed:3,800-4,000 rpm
Idle speed:1,250-1,600 rpm
Cylinder compression:0.49-0.69 MPa (5.0-7.0 kgf/cm2 , 71-100 psi) / 600 rpm
Valve clearance
Intake valve clearance:0.15±0.02 mm (0.006±0.001 in)
Exhaust valve clearance:0.20±0.02 mm (0.008±0.001 in)
Oil system
Lubrication system:Forced splash
Oil type:SAE 10W-30
Recommended oil:Honda 4-stroke or an equivalent (SE or SF)
Oil capacity:0.56 L (0.59 US. qt, 0.49 Imp. qt.)
Fuel system
Type:Horizontal type carburetor with butterfly valve
Main jet: BE60W A: #62
BE99A A: #60
BE61M A: #62
BE99B A: #62
Float height:13.7 mm (0.54 in)
Pilot screw opening: BE60W A: 2-1/8 turns out
BE99A A: 1-5/8 turns out
BE61M A: 2-1/8 turns out
BE99B A: 2-1/8 turns out
Ignition system
Type:C.D.I. (Capacitor Discharge Ignition) type magneto ignition
Ignition timing:B.T.D.C. 20° / 1,400 rpm
Spark plug:NGK: BPR6ES
Spark plug gap:0.7-0.8 mm (0.0276-0.0314 in)
Spark plug torque:18 N·m (1.8 kg·m, 13.3 ft·lb)
Ignition coil air gap0.2-0.6 mm (0.0079-0.0240 in)
Author: Sergei Wers
About: Co-founder and CEO of a multi-brand auto repair shop (engine repair, chassis repair, body repair and painting) for over 15 years. I have been developing internet sites with technical specifications for more than seven years.

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We try to use official documentation and verify the published data, but errors may occur. In addition, specifications of machinery and equipment may vary depending on markets and modifications. We do not recommend the use of this data for spare parts or repairs. Use official service manuals or parts catalogs for your product.

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