Honda GXV630

Honda GXV630The Honda GXV630 is a 688 cc, 41.98 cu·in natural aspirated V-twin four-stroke air-cooled internal combustion small gasoline engine with a vertical shaft, manufactured by Honda Motor Company for general-purpose applications.

A 78.0 mm (3.07 in) cylinder bore and 72.0 mm (2.83 in) piston stroke give the GXV630 engine a total of 688 cc of displacement. The compression ratio rating is 9.3:1.

The GXV630 engine produced 21.1 PS (15.5 kW; 20.8 HP) at 3,600 rpm of maximum horsepower and 48.3 N·m (4.9 kg·m, 35.6 ft·lb) at 2,500 rpm of maximum torque.

The Honda GXV630 features:

  • Overhead valve (OHV) design
  • Digital C.D.I. with variable timing ignition system
  • Horizontal type, two barrel, inner-vent carburetor with butterfly valve
  • Centrifugal governor
  • Forced feed lubrication system
  • Forced air cooling system
  • Electric starter

General information

Engine Specifications
Engine modelGXV630
Engine type4-stroke, OHV, V-twin
Displacement688 cm3, (41.98 cu·in)
Max. horsepower21.1 PS (15.5 kW; 20.8 HP) at 3,600 rpm
Max. torque48.3 N·m (4.9 kg·m, 35.6 ft·lb) at 2,500 rpm
Cooling systemForced air
Air cleanerDual-element type
Lubricating systemForced feed
Ignition systemDigital C.D.I. with variable timing
Fuel systemHorizontal type, two barrel, inner-vent carburetor with butterfly valve
Fuel consumption4.7 L (1.24 US gal, 1.03 Imp gal) / h
Fuel tank capacity
Fuel usedUnleaded gasoline (octane number 86 or higher)
Starting systemElectric starter
Stoping systemIgnition primary circuit ground
GovernorCentrifugal governor
PTO shaft rotationCounterclockwise (from PTO shaft side)
Dimensions (L x W X H)449 x 420 x 475 mm (17.7 x 16.5 x 18.7 in)
Dry weight46.5 kg (102.5 lbs)

Cylinder Block and Head

Cylinder block
Compression ratio:9.3:1
Cylinder bore:78.0 mm (3.07 in)
Piston stroke:72.0 mm (2.83 in)
Cylinder internal diameter (standard):78.000-78.015 mm (3.0709-3.0715 in)
Piston skirt outer diameter (standard):77.985-77.995 mm (3.0703-3.0707 in)
Number of piston rings (compression / oil):2/1
Connecting rod small end diameter (standard):18.006-18.018 mm (0.7089-0.7094 in)
Piston pin diameter:17.994-18.000 mm (0.7084-0.7087 in)
Side clearance (Top):0.050-0.080 mm (0.002-0.0031 in)
Side clearance (Second):0.050-0.080 mm (0.002-0.0031 in)
Ring end gap (Top):0.200-0.350 mm (0.0079-0.0138 in)
Ring end gap (Second):0.200-0.350 mm (0.0079-0.0138 in)
Ring end gap (Oil):0.200-0.700 mm (0.0079-0.0276 in)
Ring width (Top):1.140-1.155 mm (0.0449-0.0455 in)
Ring width (Second):1.140-1.155 mm (0.0449-0.0455 in)
Crankshaft main journal diameter:39.984-40.000 mm (1.5742-1.5748 in)
Crankpin journal diameter:44.973-44.983 mm (1.7706-1.771 in)
Cylinder head
Valve arrangement:OHV, gear driven
Valves:2(4 valves in total)
Valve steam diameter (INTAKE):5.475-5.490 mm (0.2156-0.2161 in)
Valve steam diameter (EXHAUST):5.435-5.450 mm (0.214-0.2146 in)
Valve spring free length (INTAKE):38.300 mm (1.5079 in)
Valve spring free length (EXHAUST):38.300 mm (1.5079 in)
Camshaft lobe height (INTAKE):29.506-29.706 mm (1.1617-1.1695 in)
Camshaft lobe height (EXHAUST):29.410-29.610 mm (1.1579-1.1657 in)

Tightening torque specs

Tightening torque specs
Connecting rod bolt22 Nm; 2.2 kg·m; 16 ft·lb
Cylinder nut37 Nm; 3.8 kg·m; 27 ft·lb
Oil drain plug bolt45 Nm; 4.5 kg·m; 33 ft·lb
Flywheel nut235 Nm; 24.0 kg·m; 173 ft·lb
Oil filter cartridge12 Nm; 1.2 kg·m; 9 ft·lb
Tappet adjusting nut7.5 Nm; 0.75 kg·m; 5.5 ft·lb
Governor arm nut11 Nm; 1.1 kg·m; 8 ft·lb
Fuel pump cover screw4 Nm; 0.4 kg·m; 3 ft·lb
Oil pressure switch9 Nm; 0.9 kg·m; 6.6 ft·lb

Service Data

Maximum speed:3,400 ± 150 rpm
Idle speed:1,400 ± 150 rpm
Cylinder compression:5.0-7.0 kg/cm2 (73-102 psi) at 500 rpm
Valve clearance
Intake valve clearance:0.08±0.02 mm (0.003±0.001 in)
Exhaust valve clearance:0.10±0.02 mm (0.004±0.001 in)
Oil system
Lubrication system:Forced feed
Oil type:Honda 4-stroke or an equivalent (SE or later)
Recommended oil:SAE 10W-30
Oil capacity: Without oil filter: 1.7 Liters (1.80 US qt, 1.50 Imp qt)
With oil filter: 1.9 Liters (2.01 US qt, 1.67 Imp qt)
Fuel system
Type:Horizontal type, two barrel, inner-vent carburetor with butterfly valve
Main jet: Cylinder №1: #105
Cylinder №2: #110
Float height:15.5 mm (0.6102 in)
Pilot screw opening: Cylinder №1: 2 turns out
Cylinder №2: 2-1/8 turns out
Ignition system
Type:Digital C.D.I. with variable timing
Ignition timing:9°-23° B.T.D.C.
Spark plug:NGK: ZFR5F
Spark plug gap:0.7-0.8 mm (0.0276-0.0315 in)
Ignition coil air gap0.3-0.5 mm (0.0118-0.0197 in)
Author: Sergei Wers
About: Co-founder and CEO of a multi-brand auto repair shop (engine repair, chassis repair, body repair and painting) for over 15 years. I have been developing internet sites with technical specifications for more than seven years.

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We try to use official documentation and verify the published data, but errors may occur. In addition, specifications of machinery and equipment may vary depending on markets and modifications. We do not recommend the use of this data for spare parts or repairs. Use official service manuals or parts catalogs for your product.

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