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 |
how many ounces is 0.451?
It is 0.45 Liters = 15.22 US Fluid Ounces