Specifi cations
1124 690 06 Rev. P KohlerEngines.com
CLEARANCE SPECIFICATIONS
4
CH18/CH20/
CH22/
CH620/CH621/
CH640/CH641
CH22/CH23/
CH620
8
/
CH640
8
/
CH670/CH680
CH25/
CH730/
CH740 CH750
Cylinder Bore
Bore I.D.
New 77.000/
77.025 mm
(3.0315/
3.0325 in.)
80.000/
80.025 mm
(3.1496/
3.1506 in.)
82.988/83.013 mm
(3.2672/3.2682 in.)
Max. Wear Limit 77.063 mm
(3.0340 in.)
80.065 mm
(3.1522 in.)
83.051 mm
(3.2697 in.)
Max. Out-of-Round 0.12 mm (0.0047 in.)
Max. Taper 0.05 mm (0.0020 in.)
Cylinder Head
Max. Out-of-Flatness 0.076 mm (0.003 in.) 0.1 mm (0.004 in.)
Governor
Governor Cross Shaft-to-Crankcase
Running Clearance
6 mm Shaft
8 mm Shaft
0.013/0.075 mm (0.0005/0.0030 in.)
0.025/0.126 mm (0.0009/0.0049 in.)
Cross Shaft O.D.
6 mm Shaft
New
Max. Wear Limit
8 mm Shaft
New
Max. Wear Limit
5.975/6.012 mm (0.2352/0.2367 in.)
5.962 mm (0.2347 in.)
7.949/8.000 mm (0.3129/0.3149 in.)
7.936 mm (0.3124 in.)
Governor Gear Shaft-to-Governor Gear
Running Clearance
0.015/0.140 mm (0.0006/0.0055 in.)
Gear Shaft O.D.
New
Max. Wear Limit
5.990/6.000 mm (0.2358/0.2362 in.)
5.977 mm (0.2353 in.)
Ignition
Spark Plug Gap 0.76 mm (0.030 in.)
Module Air Gap 0.28/0.33 mm (0.011/0.013 in.)
Piston, Piston Rings, and Piston Pin
Piston Style A
Piston-to-Piston Pin Running Clearance 0.006/0.017 mm (0.0002/0.0007 in.)
Pin Bore I.D.
New
Max. Wear Limit
17.006/17.012 mm (0.6695/0.6698 in.)
17.025 mm (0.6703 in.)
Pin O.D.
New
Max. Wear Limit
16.995/17.000 mm (0.6691/0.6693 in.)
16.994 mm (0.6691 in.)
Top Compression Ring-to-Groove Side Clearance 0.040/
0.080 mm
(0.0016/
0.0031 in.)
0.030/
0.076 mm
(0.0012/
0.0030 in.)
0.025/0.048 mm
(0.0010/0.0019 in.)
4
Values are in Metric units. Values in parentheses are English equivalents.
8
CH620/CH640 engines changed from 624cc to 674cc; displacement can be confi rmed on engine nameplate.