Honda G100 K2

Honda G100 K2, 2.5 HPThe Honda G100 K2 is a 98 cc (6.0 4-stroke, single-cylinder, air-coolled internal combustion small gasoline engine manufactured by Honda Motor Company.

The Honda G100K2 engine has a slide valve (L-head) design and camshaft driven by a single row chain driven by the crankshaft. The engine has a recoil starter, horizontal carburetor with butterfly valve and transistorized magneto ignition system.

The G100 K2 engine a compression ratio rating is 6.5:1, cylinder bore and piston stroke are 52.0 mm (20.5 in) and 46.0 mm (1.81 in), respectively. The Honda G100 produced 2.5 HP at 4200 rpm of maximum horsepower and 4.5 Nm (0.45 kg·m, 3.3 ft·lb) of maximum torque, depending on the engine application.

There are three versions of G100 engine:

  • Honda G100, with 76 cc of displacement and 2.0 HP or 2.2 HP of horsepower
  • Honda G100 K1, with 83 cc of displacement and 2.2 HP
  • Honda G100 K2, with 98 cc of displacement and 2.5 HP of maximum output power

General information

Engine Specifications
ModelG100 K2
Type4-stroke, side valve type (L-head), single cylinder
Displacement98 cm 3 (6.0 cu-in)
Max. horsepower2.0 HP (1.5 kW) at 4200 rpm
Max. torque3.5 Nm (0.35 kg·m, 2.5 ft·lb)
CarburetorHorizontal, butterfly valve
Cooling systemForced-air
Ignition systemTransistorized magneto
Lubricating systemSplash system
Starting systemRecoil starter
Stoping systemGround of primary circuit
Fuel usedUnleaded gasoline (octane number 86 or higher)
Fuel tank capacity1.4 L
Fuel consumption320 g/HPh
PTO shaft rotationCounterclockwise (from PTO shaft side)

Cylinder Block and Head

Cylinder block
Compression ratio:6.5:1
Bore x Stroke52 x 46 mm (20.5 in x 1.81 in in)
Sleeve internal diameter52.00 mm (20.5 in)
Cylinder Head
Warpage (limit)0.10 mm (0.004 in)
Valve Arrangement:Side valve type (L-head)

Maintenance data

Idle speed1400 ± 110 rpm
Cylinder compression6.5 kg/cm2 (637 kPa) at 800 rpm
Adjust timing ignition
Ignition timing20° B.T.D.C. (Fixed)
Adjust valve clearance
Intake valve0.08-0.16 mm (0.0031-0.0063 in)
Exhaust valve0.08-0.16 mm (0.0031-0.0063 in)
Oil system
Oil typeHonda 4-stroke “SJ”
Recommended oil10W-40
Oil capacity0.45 L
Ignition system
Spark plug NGK: BPMR-4A
Spark plug gap0.6-0.7 mm (0.024-0.028 in)

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
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We try to use verified sources and official documentation, however, differences between sources or errors in entering information may occur. We do not provide advice on technical issues related to the engines operation or repair. We do not recommend using provided information for engines repairing engines or spare parts ordering, use only official service manuals and spare-parts catalogs.


  1. this artical was very helpful,but it left out my main question, can i use a k2 connecting rod in my k1 engine..rerering to the g100 generator engine family.

  2. The specifications for The Honda G100 K2(98cc) model are very comprehensive, but it does not state the width and length of the PTO shaft! – Can any one help? – kind regards, Jeff.

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