The Honda GXV50 is a small 49 cc, (2.99 cu-in) single-cylinder, air-cooled, four-stroke cycle, internal combustion gasoline engine with vertical shaft, manufactured by Honda Motor Company.
This engine has a single-cylinder, overhead-valve, and precision camshaft design, the high compression ratio for better fuel efficiency and a ball bearing supported crankshaft for greater stability. The Honda GXV50 engine has transistorized magneto ignition, horizontal type carburetor, and recoil starter.
A 41.8 mm (1.65 in) cylinder bore and 36.0 mm (1.42 in) piston stroke give the engine a total of 49 cc (2.99 cu-in) of displacement. Compression ratio rating is 8.0:1.
The GXV50 engine produces 2.5 PS (1.8 KW; 2.5 HP) at 7,000 rpm of maximum horsepower and 3.04 Nm (0.31 kg·m; 2.24 lbf·ft) at 4,500 rpm of peak torque.
General information
Engine Specifications | |
Model | GXV50 (vertical shaft) |
Type | 4-stroke, OHV, single cylinder |
Displacement | 49 cm 3 (2.99 cu-in) |
Max. horsepower | 2.5 PS (1.8 KW; 2.5 HP) at 7,000 rpm |
Max. torque (crank PTO) | 3.04 Nm (0.31 kg·m; 2.24 lbf·ft) at 4,500 rpm |
Carburetor | Horizontal type, butterfly valve |
Cooling system | Forced-air |
Ignition system | Transistorized magneto ignition |
Lubricating system | Splash |
Starting system | Recoil or electric starter |
Stoping system | Ignition primary circuit ground |
Fuel used | Unleaded gasoline (octane number 86 or higher) |
Fuel tank capacity | 0.5 liters (0.53 US.qts, 0.44 Imp. qts) |
Fuel consumption | 250 g/HPh |
PTO shaft rotation | Counterclockwise (from PTO shaft side) |
Dimensions and Weight
S | V | |
Length, mm (in) | 249 (9.8) | |
Width, mm (in) | 286 (11.3) | |
Height, mm (in) | 225 (8.9) | 198 (7.8) |
Dry weight, kg (lb) | 5.2 (11.47) | |
Operating weight, kg (lb) |
5.7 (12.57) |
Cylinder Block and Head
Cylinder block | ||
Compression ratio: | 8.0:1 | |
Bore x Stroke | 41.8 mm X 36.0 mm (1.65 x 1.42 in) | |
Sleeve internal diameter | 41.800-41.815 mm (1.6457-1.6463 in) | |
Piston skirt outer diameter | 41.770-41.790 mm (1.6445-1.6453 in) | |
Piston ring side clearance (Top): | 0.015-0.050 mm (0.0006-0.0020 in) | |
Piston ring side clearance (Second): | 0.015-0.050 mm (0.0006-0.0020 in) | |
Piston ring end gap (Top): | 0.150-0.300 mm (0.0059-0.0118 in) | |
Piston ring end gap (Second): | 0.150-0.300 mm (0.0059-0.0118 in) | |
Ring width (Top): | 0.770-0.790 mm (0.030-0.031 in) | |
Ring width (Second): | 0.970-0.990 mm (0.038-0.039 in) | |
Connecting rod small end ID | 10.006-10.007 mm (0.3939-0.3944 in) | |
Connecting rod big end ID | 15.000-15.011 mm (0.5906-0.5910 in) | |
Crankpin outer diameter | 14.973-14.984 mm (0.5895-0.5899 in) | |
Cylinder Head | ||
Warpage (limit) | 0.10 mm (0.004 in) | |
Valve Arrangement: | OHV | |
Valves: | 2 | |
Valve stem outer diameter (INTAKE): | 3.970-3.985 mm (0.1563-0.1569 in) | |
Valve stem outer diameter (EXHAUST): | 3.935-3.950 mm (0.1549-0.1555 in) | |
Spring free length | 23.7.0 mm (0.93 in) | |
Cam height | 27.972 mm (1.1013 in) |
Tightening torque specs
Tightening torque specs | |
Spark plug | 12 Nm; 1.2 kg·m; 8.6 ft·lb |
Connecting rod bolt | 6 Nm; 0.6 kg·m; 4.3 ft·lb |
Crankcase cover bolt | 7.5 Nm; 0.75 kg·m; 5.4 ft·lb |
Oil case bolt | 7.5 Nm; 0.75 kg·m; 5.4 ft·lb |
Valve cover bolt | 6 Nm; 0.6 kg·m; 4.3 ft·lb |
Oil drain bolt | 11 Nm; 1.1 kg·m; 8 ft·lb |
Flywheel nut | 21 Nm; 2.1 kg·m; 15 ft·lb |
Fuel tank bolt | 10 Nm; 1.0 kg·m; 7 ft·lb |
Igniton coil bolt | 6 Nm; 0.6 kg·m; 4.3 ft·lb |
Fan caver stud bolt | 6 Nm; 0.6 kg·m; 4.3 ft·lb |
Governor arm nut | 7 Nm; 0.7 kg·m; 5.1 ft·lb |
Carburetor drain bolt | 4.5 Nm; 0.45 kg·m; 3.3 ft·lb |
Others | |
4 mm bolts, nuts | 3.5 Nm; 0.35 kg·m; 2.5 ft·lb |
5 mm bolts, nuts | 5.5 Nm; 0.55 kg·m; 4.0 ft·lb |
6 mm bolts, nuts | 10 Nm; 1.0 kg·m; 7 ft·lb |
Service Information
Engine | |
Maximum speed | 4,800 ± 150 rpm |
Idle speed | 2,500 ± 200 rpm |
Cylinder compression | 4.3 kg/cm2 (61.2 psi) at 1000 rpm |
Valve clearance | |
Intake valve | 0.06-0.10 mm (0.0024-0.0039 in) |
Exhaust valve | 0.09-0.13 mm (0.0035-0.0051 in) |
Oil system | |
Oil type | Honda 4-stroke or an equivalent (SE or SF) |
Recommended oil | SAE 10W-30 |
Oil capacity | 0.25 liters (0.26 US.qts, 0.22 Imp. qts) |
Ignition system | |
Ignition timing | 30° B.T.D.C. |
Spark plug | NGK: CR5HSB DENSO: U16FSR-UB |
Spark plug gap | 0.6-0.7 mm (0.024-0.028 in) |
Spark plug tightening torque | 12 Nm; 1.2 kg·m; 8.6 ft·lb |
Primary ignition coil resistance | 0.98-1.20 Ω |
Secondary ignition coil resistance | 8-10 kΩ |
Ignition coil air gap | 0.3-0.5 mm (0.012-0.020 in) |
Carburetor | |
Main jet | #55 |
Float height | 12 mm (0.47 in) |
Pilot screw opening | 1-1/8 turns out |
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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