The Honda G100 K1 is a 83 cc (5.06 cu.in.) single-cylinder air-coolled 4-stroke internal combustion small gasoline engine manufactured by Honda Motor Company since 1980. The G100 K1 is the second generation of this engine. It has larger cylinder bore and, as a result, larger displacement.
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 an electric or recoil starter, horizontal carburetor with butterfly valve and transistorized magneto or contact point breaker (CDI) ignition system.
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
The G100K1 engine a compression ratio rating is 6.5:1, cylinder bore and piston stroke are 48.0 mm (1.88 in) and 46.0 mm (1.81 in), respectively.
The Honda G100 K1 produced 2.2 HP (1.64 kW) at 4200 rpm of maximum horsepower and 3.8 Nm (0.38 kg·m) of torque.
General information
| Engine Specifications | |
| Model | G100 K1 |
| Type | 4-stroke, side valve type (L-head), single cylinder |
| Displacement | 83 cm 3 (5.06 cu-in) |
| Max. horsepower | 2.2 HP (1.64 kW) at 4200 rpm |
| Max. torque | 3.8 Nm (0.38 kg·m) |
| Carburetor | Horizontal, butterfly valve |
| Cooling system | Forced-air |
| Ignition system | Transistorized magneto or CDI |
| Lubricating system | Splash system |
| Starting system | Recoil starter |
| Stoping system | Ground of primary circuit |
| Fuel used | Unleaded gasoline (octane number 86 or higher) |
| Fuel tank capacity | 1.4 L |
| 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 | 48 x 46 mm (1.88 in x 1.81 in in) | |
| Sleeve internal diameter | 48.00 mm (1.88 in) | |
| Piston skirt outer diameter | 47.995 mm (1.8503 in) | |
| Number of piston rings (compression / oil): | 2 / 1 | |
| Ring side clearance | Top/second/oil | 0.01-0.05 mm (0.0004-0.002 in) |
| Ring end gap | Top/second | 0.25 mm (0.009 in) |
| Oil | 0.45 mm (0.017 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 | 17.98 mm (0.707 in) | |
| Cylinder Head | ||
| Warpage (limit) | 0.10 mm (0.004 in) | |
| Valve Arrangement: | Side valve type (L-head) | |
| Valves: | 2 | |
| Stem outer diameter (standard): | INTAKE | 5.490 mm (0.2161 in) |
| EXHAUST | 5.445 mm (0.2143 in) | |
| Guide internal diameter | INTAKE / EXHAUST | 5.5 mm (0.2165 in) |
| Spring free length | 27.1 mm (1.066 in) | Cam height: | INTAKE | 20.82 mm (0.8196 in) |
| EXHAUST | 20.82 mm (0.8196 in) | |
| Camshaft journal diameter: | 12.184 mm (0.4796 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 L |
| Carburetor | |
| Main jet | #62 |
| 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 ignition coil resistance | 0.7-0.9 kΩ |
| Secondary ignition coil resistance | 6.3-7.7 kΩ |
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 |
Author:
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