Honda G100 K2

Honda G100 K2The Honda G100 K2 is a 98 cc (5.98 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.

The cylinder bore is 52.0 mm (2.05 in) and the piston stroke is 46.0 mm (1.81 in). The compression ratio rating is 6.5:1.

The Honda G100 K2 engine produced 2.5 PS (1.9 kW; 2.5 HP) at 4,200 rpm of maximum output power and 3.5 N·m (0.4 kg·m, 2.6 ft·lb) of peak torque.

The Honda G100 K2 features:

  • Side valve (L-head) design
  • Transistorized magneto ignition system
  • Horizontal type carburetor with butterfly valve
  • Centrifugal govervor
  • Splash type lubrication system
  • Forced air cooling system
  • Recoil starter

General information

Engine Specifications
Engine modelG100 K2
Engine type4-stroke, L-head, single-cylinder
Displacement98 cm3, (5.98 cu·in)
Max. horsepower2.5 PS (1.9 kW; 2.5 HP) at 4,200 rpm
Max. torque3.5 N·m (0.4 kg·m, 2.6 ft·lb)
Cooling systemForced air
Lubricating systemSplash type
Ignition systemTransistorized magneto
Fuel systemHorizontal type carburetor with butterfly valve
Fuel consumption320 g/HPh
Fuel tank capacity1.4 L (0.37 US. gal. 0.31 Imp. gal.)
Fuel usedUnleaded gasoline (octane number 86 or higher)
Starting systemRecoil starter
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:6.5:1
Cylinder bore:52.0 mm (2.05 in)
Piston stroke:46.0 mm (1.81 in)
Cylinder internal diameter (standard):52.000 mm (2.0472 in)
Number of piston rings (compression / oil):2/1
Crankshaft center distance:23 mm (0.905 in)
Cylinder head
Valve arrangement:L-head, belt driven

Tightening torque specs

Tightening torque specs
Carburetor4-6 Nm; 0.4-0.6 kg·m; 2.9-4.3 ft·lb
Flywheel45-55 Nm; 4.5-5.5 kg·m; 32.5-40 ft·lb
Governor arm8-12 Nm; 0.8-1.2 kg·m; 5.8-8.7 ft·lb
Cylinder head8-12 Nm; 0.8-1.2 kg·m; 5.8-8.7 ft·lb
Crankcase cover8-12 Nm; 0.8-1.2 kg·m; 5.8-8.7 ft·lb
Connecting rod4-6 Nm; 0.4-0.6 kg·m; 2.9-4.3 ft·lb
5 mm bolts, nuts4-7 Nm; 0.4-0.7 kg·m; 2.9-5.1 ft·lb
6 mm bolts, nuts8-12 Nm; 0.8-1.2 kg·m; 5.8-8.7 ft·lb
8 mm bolts, nuts20-28 Nm; 2.0-2.8 kg·m; 14.5-20.3 ft·lb
10 mm bolts, nuts35-40 Nm; 3.5-4.0 kg·m; 25-29 ft·lb

Service Data

Idle speed:1,400±150 rpm
Cylinder compression:6.5 kg/cm2 (637 kPa) at 800 rpm
Valve clearance
Intake valve clearance:0.08-0.16 mm (0.0031-0.0063 in)
Exhaust valve clearance:0.08-0.16 mm (0.0031-0.0063 in)
Oil system
Lubrication system:Splash type
Oil type:Honda 4-stroke “SJ”
Recommended oil:SAE 10W-40
Oil capacity:0.45 L (0.48 US. qt, 0.4 Imp. qt.)
Fuel system
Type:Horizontal type carburetor with butterfly valve
Ignition system
Type:Transistorized magneto
Spark plug:NGK: BPMR-4A
Spark plug gap:0.6-0.7 mm (0.0236-0.0276 in)


Manufacturer or BrandModels
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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