The Honda G80 is a 296 cc (18.0 cu.in.) single-cylinder air-coolled 4-stroke internal combustion small gasoline engine manufactured by Honda Motor Company since 1975 for general-purpose applications.
The Honda G80 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 high voltage ignition.
An 80.0 mm (3.2 in) cylinder bore and 59.0 mm (2.3 in) piston stroke give the engine a total of 296 cc (18.0 cu.in.) of displacement. The compression ratio was 6.3:1. The G80 produced 8.0 HP (5.9 kW) at 4000 rpm of maximum horsepower and continuous rated output was 6.0 HP (4.5 kW) at 3600 rpm. The maximum torque was 15.7 Nm (1.6 kg·m) at 2500 rpm. The dry weight of the Honda G80 engine was 30.4 kg (67.0 lbs).
General information
Engine Specifications | |
Model | G80 |
Type | 4-stroke, side valve type (L-head), single cylinder |
Displacement | 296 cm 3 (18.0 cu-in) |
Max. horsepower | 8.0 HP (5.9 kW) at 4,000 rpm |
Max. torque | 15.7 Nm (1.6 kg·m) at 2,500 rpm |
Carburetor | Horizontal, butterfly valve |
Cooling system | Forced-air |
Ignition system | High voltage ignition |
Lubricating system | Splash system |
Starting system | Recoil starter |
Stoping system | Ground switch |
Fuel used | Unleaded gasoline (octane number 86 or higher) |
Fuel tank capacity | 6.9 L (1.8 US gal., 1.5 Imp. gal.) |
Fuel consumption | 285 g/HPh |
PTO shaft rotation | Counterclockwise (from PTO shaft side) |
Cylinder Block and Head
Cylinder block | ||
Compression ratio: | 6.3:1 | |
Bore x Stroke | 80 X 59 mm (3.2 x 2.3 in) | |
Sleeve internal diameter | 80.00 mm (3.150 in) | |
Piston skirt outer diameter | 79.97 mm (3.148 in) | |
Ring width | Top | 2.48 mm (0.098 in) |
Second/Oil | 2.49 mm (0.098 in) | |
Ring Side Clearance | Top | 0.02 mm (0.0008 in) |
Second/Oil | 0.01 mm (0.0004 in) | |
Piston pin outer diameter | 19.0 mm (0.748 in) | |
Cylinder Head | ||
Warpage (max) | 0.2 mm (0.01 in) | |
Valve Arrangement: | Side valve type (L-head) | |
Valves: | 2 | |
Stem outer diameter (standard): | INTAKE | 6.97 mm (0.274 in) |
EXHAUST | 6.93 mm (0.273 in) | |
Valve guide internal diameter | 7.00 mm (0.276 in) | |
Cam height: | INTAKE | 35.18 mm (1.385 in) |
EXHAUST | 35.18 mm (1.385 in) |
Maintenance data
Engine | |
Cylinder compression | 4.0 kg/cm2 at 450-600 rpm |
Tappet clearance | |
Intake valve | 0.06-0.11 mm (0.0023-0.0043) |
Exhaust valve | 0.06-0.11 mm (0.0023-0.0043) |
Oil system | |
Oil type | Honda 4-stroke or an equivalent (SG, SF) |
Recommended oil | SAE 10W-30, 10W-40 |
Oil capacity | 1.1 L (2.3 US pt, 1.9 lmp pt) |
Ignition system | |
Ignition timing | 25 ° B.T.D.C (Fixed) |
Spark plug | NGK: BR6HS, B6HS |
Spark plug gap | 0.6-0.7 mm (0.024-0.028 in) |
Tightening torque specs
Tightening torque specs | |
Fuel tank (8 mm nut, bolt) | 20-28 Nm; 2.0-2.8 kg·m; 14.5-20.2 ft·lb |
Side cover (10 mm bolt) | 35-40 Nm; 3.5-4.0 kg·m; 25.3-28.9 ft·lb |
Cylinder Head (10 mm bolt) | 35-40 Nm; 3.5-4.0 kg·m; 25.3-28.9 ft·lb |
Cylinder (6 mm bolt) | 8-12 Nm; 0.8-1.2 kg·m; 5.8-8.7 ft·lb |
Cylinder (8 mm bolt) | 20-28 Nm; 2.0-2.8 kg·m; 14.5-20.2 ft·lb |
Camshaft center (6 mm bolt) | 10-15 Nm; 1.0-1.5 kg·m; 7.2-10.8 ft·lb |
Starter pulley (6 mm bolt) | 8-12 Nm; 0.8-1.2 kg·m; 5.8-8.7 ft·lb |
Flywheel (17 mm nut) | 70-80 Nm; 7.0-8.0 kg·m; 50.6-57.9 ft·lb |
Muffler (6 mm nut) | 8-12 Nm; 0.8-1.2 kg·m; 5.8-8.7 ft·lb |
Muffler (8 mm bolt) | 20-28 Nm; 2.0-2.8 kg·m; 14.5-20.2 ft·lb |
Carburetor (6 mm nut) | 8-12 Nm; 0.8-1.2 kg·m; 5.8-8.7 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.
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