Kohler Command Pro EFI ECH940 Service Manual page 79

4. Before installing new rings on piston, place top 2
rings, each in turn, in its running area in cylinder
bore and check end gap. Top compression ring end
gap clearance is 0.125/0.304 mm (0.0049/0.0120
in.) for a new bore, or 0.515 mm (0.0203 in.) for a
used bore. Middle compression ring end cap is
0.900/1.179 mm (0.0354/0.0464 in.) for a new bore,
or 1.432 mm (0.0564 in.) for a used bore.
5. After installing new compression (top and middle)
rings on piston, make sure top compression ring-to-
groove side clearance and is 0.030/0.070 mm
(0.0010/0.0026 in.) and middle compression ring-to-
groove side clearance 0.030/0.070 mm
(0.0010/0.0026 in.). If side clearance is greater than
specifi ed, a new piston must be used.
Install New Piston Rings
Piston Ring Orientation
F
A
10°
10°
B
Top Oil Ring Rail
A
Gap
Intermediate Ring
C
Gap
E Top Ring Gap
NOTE: Rings must be installed correctly. Ring
installation instructions are usually included with
new ring sets. Follow instructions carefully. Use
a piston ring expander to install rings. Install
bottom (oil control) ring fi rst and top
compression ring last.
To install new piston rings, proceed as follows:
1. Oil control ring (bottom groove): Install expander and
then rails. Make sure ends of expander are not
overlapped.
2. Middle compression ring (center groove): Install
center ring using a piston ring installation tool. Make
sure identifi cation mark is up or colored dye stripe
(if contained), is to left of end gap.
3. Top compression ring (top groove): Install top ring
using a piston ring expander. Make sure
identifi cation mark is up or colored dye stripe
(if contained), is to left of end gap.
62 690 13 Rev. A
E
D
C
Bottom Oil Ring Rail
B
Gap
Oil Ring Expander
D
Gap
F FLY Stamp
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Disassembly/Inspection and Service
Remove Crankshaft
NOTE: If crankpin is reground, visually check to ensure
that fi llet blends smoothly with crankpin surface.
Carefully pull crankshaft from crankcase. Note thrust
washers and shims if used.
Inspection and Service
Crankshaft Components and Details
A Self-Tapping Screw
C Plug
G
E
Fillet Must Blend Smoothly with Bearing Journal
E
F High Point from Fillet Intersections
G
H This Fillet Area Must Be Completely Smooth
Inspect gear teeth of crankshaft. If teeth are badly worn,
chipped, or some are missing, replacement of crankshaft
will be necessary.
Inspect crankshaft bearing surfaces for scoring,
grooving, etc. Replaceable bearing is used in crankshaft
bore of closure plate and/or crankcase. Do not replace
bearing unless they show signs of damage or are out of
running clearance 0.040/0.167 mm (0.0015/0.0065 in.).
If crankshaft turns easily, without noise, and there is no
evidence of scoring, grooving, etc., on races or bearing
surfaces, bearing can be reused.
A
B
C
D
B Flat Washer
D Crankshaft
F
H
Surface
45° Minimum
79