The Honda G100 is a 76 cc (4.6 cu.in.) four4-stroke, single-cylinder, air-cooled, internal combustion small gasoline engine manufactured by Honda Motor Company since 1980.
The Honda G100 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 flywheel magneto or CDI ignition system.
The G100 engine a compression ratio rating is 6.5:1, cylinder bore and piston stroke are 46.0 mm (1.81 in) and 46.0 mm (1.81 in), respectively.
The Honda G100 produced 2.0 PS (1.5 KW; 2.0 HP) or 2.2 PS (1.6 KW; 2.1 HP) at 4,200 rpm of maximum horsepower and 3.3 Nm (0.34 kg·m; 2.44 lbf·ft) or 3.5 Nm (0.36 kg·m; 2.58 lbf·ft) 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 | |
Model | G100 |
Type | 4-stroke, side valve type (L-head), single cylinder |
Displacement | 76 cm 3 (4.6 cu-in) |
Max. horsepower |
2.0 PS (1.5 KW; 2.0 HP) at 4,200 rpm 2.2 PS (1.6 KW; 2.1 HP) at 4,200 rpm |
Max. torque |
3.3 Nm (0.34 kg·m; 2.44 lbf·ft) 3.5 Nm (0.36 kg·m; 2.58 lbf·ft) |
Carburetor | Horizontal, butterfly valve |
Cooling system | Forced-air |
Ignition system | Flywheel magneto |
Lubricating system | Splash type |
Starting system | Recoil starter |
Stoping system | Ground of primary circuit |
Fuel used | Unleaded gasoline (octane number 86 or higher) |
Fuel tank capacity | 1.4 liters (1.5 US.qts, 1.23 Imp. qts) |
Fuel consumption | 320 g/HPh |
PTO shaft rotation | Counterclockwise (from PTO shaft side) |
Cylinder Block and Head
Cylinder block | ||
Compression ratio: | 6.5:1 | |
Bore x Stroke | 46 x 46 mm (1.81 in x 1.81 in in) | |
Sleeve internal diameter | 46.00 mm (1.811 in) | |
Piston skirt outer diameter | 45.980 mm (1.810 in) | |
Number of piston rings (compression / oil): | 2 / 1 | |
Piston ring side clearance (Top): | 0.025-0.055 mm (0.0009-0.0022 in) | |
Piston ring side clearance (Second): | 0.010-0.040 mm (0.0004-0.0016 in) | |
Piston ring side clearance (Oil): | 0.010-0.040 mm (0.0004-0.0016 in) | |
Piston ring end gap (Top): | 0.150-0.350 mm (0.006-0.014 in) | |
Piston ring end gap (Second): | 0.150-0.350 mm (0.006-0.014 in) | |
Piston ring end gap (Oil): | 0.150-0.350 mm (0.006-0.014 in) | |
Connecting rod small end ID | 10.0 mm (0.393 in) | |
Connecting rod big end ID | 18.0 mm (0.708 in) | |
Crankpin outer diameter | 17.973 mm (0.7076 in) | |
Cylinder Head | ||
Warpage (limit) | 0.10 mm (0.004 in) | |
Valve Arrangement: | Side valve type (L-head) | |
Valves: | 2 | |
Valve stem outer diameter (INTAKE): | 5.490 mm (0.2161 in) | |
Valve stem outer diameter (EXHAUST): | 5.445 mm (0.2143 in) | |
Valve stem outer diameter (INTAKE): | 5.500 mm (0.2165 in) | |
Valve stem outer diameter (EXHAUST): | 5.500 mm (0.2165 in) | |
Spring free length | 27.1 mm (1.066 in) | |
Camshaft cam height (INTAKE): | 18.100-18.400 mm (0.713-0.724 in) | |
Camshaft cam height (EXHAUST): | 18.100-18.400 mm (0.713-0.724 in) |
Maintenance data
Engine | |
Idle speed | 1400 ± 110 rpm |
Cylinder compression | 6.5 kg/cm2 (637 kPa) at 800 rpm |
Adjust timing ignition | |
Ignition timing | 20° B.T.D.C. (Fixed) |
Adjust valve clearance | |
Intake valve | 0.08-0.16 mm (0.0031-0.0063 in) |
Exhaust valve | 0.08-0.16 mm (0.0031-0.0063 in) |
Oil system | |
Oil type | Honda 4-stroke “SE” |
Recommended oil | 10W-40 |
Oil capacity | 0.45 liters (0.48 US.qts, 0.4 Imp. qts) |
Carburetor | |
Main jet | #55 |
Pilot screw | 1-3/8 |
Float height | 6.7-9.7 mm (0.26-0.28 in) |
Ignition system | |
Spark plug |
NGK: BM4A, BMR4A NIPPON DENSO: W14M-U, W14MR-U |
Spark plug gap | 0.6-0.7 mm (0.024-0.028 in) |
Primary winding ignition coil resistance | 0.49 Ω±10% |
Secondary winding ignition coil resistance | 4.0 kΩ±10% |
Tightening torque specs
Tightening torque specs | |
Carburetor | 4-6 Nm; 0.4-0.6 kg·m; 2.9-4.3 ft·lb |
Flywheel | 45-55 Nm; 4.5-5.5 kg·m; 32.5-40 ft·lb |
Governor arm | 8-12 Nm; 0.8-1.2 kg·m; 5.8-8.7 ft·lb |
Cylinder head | 8-12 Nm; 0.8-1.2 kg·m; 5.8-8.7 ft·lb |
Crankcase cover | 8-12 Nm; 0.8-1.2 kg·m; 5.8-8.7 ft·lb |
Connecting rod | 4-6 Nm; 0.4-0.6 kg·m; 2.9-4.3 ft·lb |
Others | |
5 mm bolts, nuts | 4-7 Nm; 0.4-0.7 kg·m; 2.9-5.1 ft·lb |
6 mm bolts, nuts | 8-12 Nm; 0.8-1.2 kg·m; 5.8-8.7 ft·lb |
8 mm bolts, nuts | 20-28 Nm; 2.0-2.8 kg·m; 14.5-20.3 ft·lb |
10 mm bolts, nuts | 35-40 Nm; 3.5-4.0 kg·m; 25-29 ft·lb |
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.
how many ounces is 0.451?
It is 0.45 Liters = 15.22 US Fluid Ounces