The Honda GXV390 is a 389 cc, (23.74 cu·in) natural aspirated single-cylinder four-stroke air-cooled internal combustion small gasoline engine with a vertical PTO shaft, manufactured by Honda Motor Company for general-purpose applications.
It has an 88.0 mm (3.46 in) cylinder bore and 64.0 mm (2.52 in) piston stroke. The compression ratio rating is 7.7:1.
This engine produced 13.2 PS (9.7 kW; 13.0 HP) at 3,600 rpm of horsepower and 28.0 N·m (2.9 kg·m, 20.6 ft·lb) at 2,500 rpm of torque.
The Honda GXV390 features:
- OHV design
- Vertical PTO shaft
- Transistorized magneto ignition system
- Horizontal type carburetor with butterfly valve
- Centrifugal govervor
- Splash type lubrication system
- Forced air cooling system
- Recoil or electric starter
General information
Engine Specifications |
Engine model |
GXV390 |
Engine type |
4-stroke, OHV, single-cylinder |
Displacement |
389 cm3, (23.74 cu·in) |
Max. horsepower |
13.2 PS (9.7 kW; 13.0 HP) at 3,600 rpm |
Max. torque |
28.0 N·m (2.9 kg·m, 20.6 ft·lb) at 2,500 rpm |
Cooling system |
Forced air |
Air cleaner |
Dual element type, oil-bath type, cyclone type |
Lubricating system |
Splash type |
Ignition system |
Transistorized magneto ignition |
Fuel system |
Horizontal type carburetor with butterfly valve |
Fuel tank capacity |
2.3 L (0.61 US. gal. 0.51 Imp. gal.) |
Fuel used |
Unleaded gasoline (octane number 86 or higher) |
Starting system |
Recoil or electric starter |
Stoping system |
Ignition primary circuit ground |
Governor |
Centrifugal govervor |
PTO shaft rotation |
Counterclockwise (from PTO shaft side) |
Dimensions (L x W X H) |
430 x 385 x 410 mm (16.9 x 15.2 x 16.1 in) |
Dry weight |
33.0 kg (72.8 lbs) |
Cylinder Block and Head
Cylinder block |
Compression ratio: |
7.7:1 |
Cylinder bore: |
88.0 mm (3.46 in) |
Piston stroke: |
64.0 mm (2.52 in) |
Cylinder internal diameter (standard): |
88.000 mm (3.4646 in) |
Piston skirt outer diameter (standard): |
87.985 mm (3.464 in) |
Number of piston rings (compression / oil): |
2/1 |
Connecting rod big end diameter (standard): |
36.025-36.039 mm (1.4183-1.4189 in) |
Connecting rod small end diameter (standard): |
20.005-20.020 mm (0.7876-0.7882 in) |
Piston pin diameter: |
20.000 mm (0.7874 in) |
Side clearance (Top): |
0.030-0.060 mm (0.0012-0.0024 in) |
Side clearance (Second): |
0.030-0.060 mm (0.0012-0.0024 in) |
Ring end gap (Top): |
0.20-1.175 mm (0.0079-0.0463 in) |
Ring end gap (Second): |
0.20-1.175 mm (0.0079-0.0463 in) |
Ring width (Top): |
1.160 mm (0.0457 in) |
Ring width (Second): |
1.160 mm (0.0457 in) |
Crankpin journal diameter: |
35.975-35.985 mm (1.4163-1.4167 in) |
Cylinder head |
Valve arrangement: |
OHV, gear driven |
Valves: |
2 |
Valve steam diameter (INTAKE): |
6.590 mm (0.2594 in) |
Valve steam diameter (EXHAUST): |
6.550 mm (0.2579 in) |
Camshaft lobe height (INTAKE): |
32.60 mm (1.2835 in) |
Camshaft lobe height (EXHAUST): |
32.09 mm (1.2634 in) |
Camshaft journal diameter : |
16.000 mm (0.6299 in) |
Tightening torque
Tightening torque specs |
Connecting rod bolt |
14 Nm; 1.4 kg·m; 10 ft·lb |
Cylinder head bolt |
35 Nm; 3.5 kg·m; 25 ft·lb |
Flywheel nut |
115 Nm; 11.5 kg·m; 83 ft·lb |
Pivot adjusting nut |
10 Nm; 1.0 kg·m; 7 ft·lb |
Push rod guide pivot bolt |
24 Nm; 2.4 kg·m; 17 ft·lb |
Oil pan bolt |
24 Nm; 2.4 kg·m; 17 ft·lb |
Air cleaner body cap nut |
9 Nm; 0.9 kg·m; 6.5 ft·lb |
Muffler mounting nut |
24 Nm; 2.4 kg·m; 17 ft·lb |
Exhaust pipe mounting nut |
24 Nm; 2.4 kg·m; 17 ft·lb |
Oil drain plug |
45 Nm; 4.5 kg·m; 34 ft·lb |
Cylinder head cover bolt |
9 Nm; 0.9 kg·m; 6.5 ft·lb |
Fuel tank bolt |
24 Nm; 2.4 kg·m; 17 ft·lb |
Standard torque values |
Bolt, nut (5 mm) |
5.5 Nm; 0.55 kg·m; 4.0 ft·lb |
Bolt, nut (6 mm) |
10 Nm; 1.0 kg·m; 7 ft·lb |
Bolt, nut (8 mm) |
24 Nm; 2.4 kg·m; 17 ft·lb |
Bolt, nut (10 mm) |
37.5 Nm; 3.75 kg·m; 27 ft·lb |
Bolt, nut (12 mm) |
55 Nm; 5.5 kg·m; 40 ft·lb |
Service Data
Engine |
Maximum speed: |
3,400±150 rpm |
Idle speed: |
1,400 ±150 rpm rpm |
Cylinder compression: |
5.0-8.5 kg/cm2 (71-151 psi) at 600 rpm |
Valve clearance |
Intake valve clearance: |
0.08-0.12 mm (0.0031-0.0047 in) |
Exhaust valve clearance: |
0.13-0.17 mm (0.0051-0.0067 in) |
Oil system |
Lubrication system: |
Splash type |
Oil type: |
Honda 4-stroke or an equivalent (SE or later) |
Recommended oil: |
SAE 10W-30 |
Oil capacity: |
1.1 L (1.16 US. qt, 0.97 Imp. qt.) |
Fuel system |
Type: |
Horizontal type carburetor with butterfly valve |
Main jet: |
#95 |
Float height: |
11.9-14.5 mm (0.4685 in) |
Pilot screw opening: |
2-1/2 turns out |
Ignition system |
Type: |
Transistorized magneto ignition |
Ignition timing: |
B.T.D.C. 20° (Fixed) |
Spark plug: |
NGK: BPR5ES, NIPPONDENSO: W16EPR-U |
Spark plug gap: |
0.7-0.8 mm (0.0276-0.0315 in) |
Ignition coil air gap |
0.4±0.2 mm (0.016±0.008 in) |
Applications
Be the first to comment