Kohler CV640

Kohler CV640The Kohler CV640 is a 624 cc, (38.0 cu·in) for early version or 674 cc, (41.0 cu·in) for later version V-twin air-cooled four-stroke internal combustion gasoline engine from the Command PRO series, manufactured by Kohler Co.

The Kohler CV640 engine has an OHV (overhead valve) design, an aluminum block with cast iron cylinder liners, vertical PTO-shaft, pressurized lubrication system. This engine is equipped with a carburetor (Nikki or Keihin) with a fixed main jet and one of these ignition systems: CDI/MDI, ASAM/DSAM, DSAI (Digital Spark Advance Ignition).

The cylinder bore and the piston stroke are 77.0 mm (3.03 in) and 67.0 mm (2.64 in), respectively for the CV640 engine with 624 cc of displacement, and 80.0 mm (3.15 in) and 67.0 mm (2.64 in), respectively for 674 cc engine. Compression ratio rating is 8.5:1.

The Kohler CV640 engine produced 20.3 PS (14.9 KW; 20.0 HP) at 3,600 rpm or 20.8 PS (15.3 KW; 20.5 HP) at 3,600 rpm of horsepower and 45.1 Nm (4.6 kg·m; 33.4 ft·lb) at 2,400 rpm or 47.0 Nm (4.79 kg·m; 34.69 ft·lb) at 2,400 rpm of torque.

The breakdown of the engine code is as follows:

  • C – Command series
  • V – Vertical PTO shaft
  • 640 – Numerical designation

General information

Engine Specifications
ModelCommand PRO CV640
Type4-stroke, OHV, V-twin
Displacement 624 cm 3 (38.0 cu-in)
674 cm 3 (41.0 cu-in)
Max. horsepower 624 cc: 20.3 PS (14.9 KW; 20.0 HP) at 3,600 rpm
674 cc: 20.8 PS (15.3 KW; 20.5 HP) at 3,600 rpm
Max. torque 624 cc: 45.1 Nm (4.6 kg·m; 33.4 ft·lb) at 2,400 rpm
674 cc: 47.0 Nm (4.8 kg·m; 34.7 ft·lb) at 2,400 rpm
Fuel systemCarburetor with a fixed main jet (Nikki or Keihin)
Cooling systemForced-air
Ignition systemCDI/MDI, ASAM/DSAM, DSAI (Digital Spark Advance Ignition)
Lubricating systemPressurized lubrication
Starting systemElectric starter
Fuel usedUnleaded gasoline (octane number 86 or higher)
Dimensions (L x W X H) 624 cc: 538 x 451 x 363 mm (21.2 x 17.7 x 14.3 in)
674 cc: 452 x 451 x 358 mm (17.8 x 17.7 x 14.1 in)
Dry weight41.0 kg (90.0 lbs)

Cylinder Block and Head

Cylinder block
Compression ratio:8.5:1
Bore x Stroke 624 cc: 77.0 mm X 67.0 mm (3.03 x 2.64 in)
674 cc: 80.0 mm X 67.0 mm (3.15 x 2.64 in)
Sleeve internal diameter 624 cc: 77.000-77.025 mm (3.0315-3.0325 in)
674 cc: 80.000-80.025 mm (3.1496-3.1506 in)
Number of piston rings (compression / oil):2 / 1
624 cc
Thrust face outer diameter76.943-76.961 mm (3.0292-3.0299 in)
Piston pin outer diameter16.995-17.000 mm (0.6691-0.6693 in)
Ring-to-groove side clearance:Top0.040-0.080 mm (0.0016-0.0031 in)
Second0.040-0.080 mm (0.0016-0.0031 in)
Oil0.060-0.202 mm (0.0024-0.0080 in)
Ring end gap:Top0.250-0.450 mm (0.0098-0.0177 in)
Second0.250-0.450 mm (0.0098-0.0177 in)
674 cc
Piston style A
Thrust face outer diameter79.943-79.961 mm (3.1473-3.1480 in)
Piston pin outer diameter16.995-17.000 mm (0.6691-0.6693 in)
Ring-to-groove side clearance:Top0.030-0.076 mm (0.0012-0.0030 in)
Second0.030-0.076 mm (0.0012-0.0030 in)
Oil0.046-0.196 mm (0.0018-0.0077 in)
Ring end gap:Top0.180-0.460 mm (0.0071-0.0181 in)
Second0.180-0.460 mm (0.0071-0.0181 in)
Piston style B
Thrust face outer diameter79.966 mm (3.1483 in)
Piston pin outer diameter16.995-17.000 mm (0.6691-0.6693 in)
Ring-to-groove side clearance:Top0.030-0.070 mm (0.001-0.0026 in)
Second0.030-0.070 mm (0.001-0.0026 in)
Oil0.060-0.190 mm (0.0022-0.0073 in)
Ring end gap:Top0.100-0.279 mm (0.0039-0.0110 in)
Second1.400-1.679 mm (0.0551-0.0661 in)
Crankshaft main journal diameter:40.913-40.935 mm (1.6107-1.6116 in)
Crankpin journal diameter:35.955-35.973 mm (1.4155-1.4163 in)
Cylinder Head
Valve Arrangement:OHV, gear drive
Valves:4 (2 per cylinder)
Valve head diameter:INTAKE33.370-33.630 mm (1.3138-1.324 in)
EXHAUST29.370-29.630 mm (1.1563-1.1665 in)
Stem outer diameter:INTAKE6.982-7.000 mm (0.2749-0.2756 in)
EXHAUST6.970-6.988 mm (0.2744-0.2751 in)

Tightening torque specs

Tightening torque specs
Cylinder head Nut (torque in 2 increments):
Step 1: 16.9 Nm (1.72 kg·m; 12.5 ft·lb)
Step 2: 35.5 Nm (3.62 kg·m; 26.2 ft·lb)
Bolt (torque in 2 increments)
Step 1: 22.6 Nm (2.31 kg·m; 16.7 ft·lb)
Step 2: 41.8 Nm (4.26 kg·m; 30.8 ft·lb)
Flywheel66.4 Nm (6.77 kg·m; 49 ft·lb)
Spark plug27 Nm (2.75 kg·m; 20.0 ft·lb)

Service Information

Oil system
Oil typeAPI SG, SH, SJ, or higher
Recommended oilSAE 10W-30
Oil capacity W/o oil filter: 1.7 L (1.8 US. qt, 1.5 Imp. qt.)
With oil filter: 1.9 L (2.0 US.qts, 1.7 Imp. qts)
Ignition system
Spark plugChampion RC12YC
Spark plug gap0.76 mm (0.030 in)
Ignition module air gap0.280-0.330 mm (0.011-0.013 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.

ATTENTION! Dear visitors, this site is not a trading platform, an official dealer or a spare parts supplier, so we do not have any price lists or spare parts catalogs. We are an information portal and provide the technical specifications of gasoline and diesel engines.

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.

Be the first to comment

Leave a Reply

Your email address will not be published.