Honda G65

Honda G65The Honda G65 is a 240 cc (14.65 cu·in) natural aspirated single-cylinder four-stroke air-cooled internal combustion small gasoline engine with a horizontal shaft, manufactured by Honda Motor Company for general-purpose applications.

Cylinder bore and piston stroke are 72.0 mm (2.83 in) and 59.0 mm (2.32 in), respectively. The compression ratio rating is 6.1:1.

The G65 engine produced 6.8 PS (5.0 kW; 6.7 HP) at 4,000 rpm of maximum horsepower and 12.5 N·m (1.25 kg·m, 9 ft·lb) at 3,000 rpm of maximum torque.

The Honda G65 features:

  • L-head design
  • Flywheel magneto ignition system
  • Horizontal type carburetor with butterfly valve
  • Centrifugal govervor
  • Splash lubrication system
  • Forced air cooling system
  • Recoil starter or rope starter, starter motor for GS65 version

General information

Engine Specifications
Engine modelG65 / GS65
Engine type4-stroke, L-head, single-cylinder
Displacement240 cm3, (14.65 cu·in)
Max. horsepower6.8 PS (5.0 kW; 6.7 HP) at 4,000 rpm
Max. torque12.5 N·m (1.25 kg·m, 9 ft·lb) at 3,000 rpm
Cooling systemForced air
Air cleaner Semi-dry type,
Oil bath type
Lubricating systemSplash
Ignition systemFlywheel magneto
Fuel systemHorizontal type carburetor with butterfly valve
Fuel consumption300 g/PSh
Fuel tank capacity6.9 L (1.82 US. gal. 1.52 Imp. gal.)
Fuel usedUnleaded gasoline (octane number 86 or higher)
Starting system Recoil starter or rope starter
GS65: Starter motor
Stoping systemIgnition primary circuit ground
GovernorCentrifugal govervor
PTO shaft rotationCounterclockwise (from PTO shaft side)
Dimensions (L x W X H)
Dry weight

Cylinder Block and Head

Cylinder block
Compression ratio:6.1:1
Cylinder bore:72.0 mm (2.83 in)
Piston stroke:59.0 mm (2.32 in)
Cylinder internal diameter (standard):72.000 mm (2.8346 in)
Piston skirt outer diameter (standard):71.970 mm (2.8335 in)
Number of piston rings (compression / oil):2/1
Piston pin diameter:19.000 mm (0.748 in)
Side clearance (Top):0.020 mm (0.0008 in)
Side clearance (Second):0.010 mm (0.0004 in)
Side clearance (Oil):0.010 mm (0.0004 in)
Ring width (Top):2.480 mm (0.0976 in)
Ring width (Second):2.490 mm (0.098 in)
Crankshaft center distance:29.5 mm (1.16 in)
Cylinder head
Valve arrangement:L-head
Valves:2
Valve steam diameter (INTAKE):6.970 mm (0.2744 in)
Valve steam diameter (EXHAUST):6.930 mm (0.2728 in)
Camshaft lobe height (INTAKE):35.180 mm (1.385 in)
Camshaft lobe height (EXHAUST):35.180 mm (1.385 in)

Tightening torque specs

Tightening torque specs
Fuel tank (8 mm nut, bolt)20-28 Nm; 2.0-2.8 kg·m; 14.5-20.2 ft·lb
Side cover (8 mm bolt)20-25 Nm; 2.0-2.5 kg·m; 14.5-18.1 ft·lb
Cylinder Head (8 mm bolt)20-25 Nm; 2.0-2.5 kg·m; 14.5-18.1 ft·lb
Cylinder (6 mm bolt)8-12 Nm; 0.8-1.2 kg·m; 5.8-8.7 ft·lb
Cylinder (8 mm bolt)20-28 Nm; 2.0-2.8 kg·m; 14.5-20.2 ft·lb
Camshaft center (6 mm bolt)10-15 Nm; 1.0-1.5 kg·m; 7.2-10.8 ft·lb
Starter pulley (6 mm bolt)8-12 Nm; 0.8-1.2 kg·m; 5.8-8.7 ft·lb
Flywheel (17 mm nut)70-80 Nm; 7.0-8.0 kg·m; 50.6-57.9 ft·lb
Muffler (6 mm nut)8-12 Nm; 0.8-1.2 kg·m; 5.8-8.7 ft·lb
Carburetor (6 mm nut)8-12 Nm; 0.8-1.2 kg·m; 5.8-8.7 ft·lb

Service Data

Cylinder compression:4.0 kg/cm2 at 450-600 rpm
Valve clearance
Intake valve clearance:0.06-0.11 mm (0.0024-0.0043 in)
Exhaust valve clearance:0.06-0.11 mm (0.0024-0.0043 in)
Oil system
Lubrication system:Splash type
Oil type:Honda 4-stroke or an equivalent (SG, SF)
Recommended oil:SAE 10W-30, 10W-40
Oil capacity:0.82 L (0.87 US. qt, 0.72 Imp. qt.)
Fuel system
Type:Horizontal type carburetor with butterfly valve
Fuel tank capacity6.9 L (1.82 US. gal. 1.52 Imp. gal.)
Ignition system
Type:Flywheel magneto
Ignition timing:25° B.T.D.C (Fixed)
Spark plug:NGK BR6HS, B6HS
Spark plug gap:0.6-0.7 mm (0.0236-0.0276 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.

1 Comment

  1. Have a honda g65 generator carburetor has been stripped down and in a box in bits. I can’t work out which way the jet ports go. Main no problem it is the little short ones that I am not sure about. Please can you help me with this. REGARDS Charles Baty.

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