For further details,
refer to the appropriate section.
Cylinder Block
1. |
Check the cylinder block for scores, rust and
corrosion. Also check for cracks or any other defects. Replace the
block if defective. |
2. |
Measure the cylinder bore with a cylinder
gauge at the three levels indicated, in the directions A and
B.
Level 2: Center of cylinder

|
3. |
If the cylinder bores show more than the
specified out-of-round or taper, or if the cylidner walls are badly
scuffed or scored, the cylinder block should be rebored and honed.
New oversize pistons and rings should be installed.
Standard
value
Cylinder bore : 86.7 mm (3.41
in.)
Out-of-round and taper of cylinder bore
:
Max. 0.02 mm (0.0008
in.)
| |
4. |
If a ridge exists at the top of the cylinder,
cut it off with a ridge reamer. |
5. |
Oversize pistons are available in two
sizes.
Piston service
size and mark mm (in.)
0.25 (0.010) O.S : 0.25
0.50 (0.010) O.S :
0.50
| |
6. |
To rebore the cylinder bore to the oversize,
maintain the specified clearance between the oversize piston and the
bore and make sure that all used pistons are the same oversize. The
standard measurement of the piston outside diameter is taken at a
level of 15.5mm (0.61in.) above the bottom ofthe piston skirt and
across the thrust faces.
Piston-to-cylinder clearance
0.01 ~ 0.03mm (0.0004 ~
0.0012in.)
|

|
7. |
Check for damage or cracks in the
cylinders. |
8. |
Check the top surface of the cylinder block
for flatness. If the top surface exceeds the limit, grind to the
minimum limit or replace.
Standard
value
Flatness of gasket surface : Max. 0.03mm
(0.0012in.)
Service limit
Flatness of gasket surface : 0.05mm
(0.0020in.)
|
When the cylinder head is assembled,
grinding less than 0.2mm (0.008in.) is
permissible.

| |
Boring Cylinder
1. |
Oversize pistons should be selected according
to the largest bore cylinder.
Identification
Mark
|
Size
|
0.25 0.50
|
0.25mm
(0.010in.) 0.50mm
(0.020in.)
|
The size of piston is stamped on top of
the
piston. | |
2. |
Measure the outside diameter of the piston to
be used. |
3. |
According to the measured O.D., calculate the
new bore size.
New bore size = Piston O.D + 0.01 to 0.03 mm
(0.0004 to 0.0012 in.) (clearance between piston and cylinder) -
0.01 mm (0.0004 in.) (honing
margin.) |
4. |
Bore each of the cylinders to the calculated
size.
To prevent distortion that may result
from temperature rise during honing, bore the cylinder holes
in the firing
order. | |
5. |
Hone the cylinders, finishing them to the
proper dimension (piston outside diameter + gap with
cylinder). |
6. |
Check the clearance between the piston and
cylinder.
Standard : 0.01 ~ 0.03mm (0.0004 ~
0.0012in.)
|
When boring the cylinders, finish all of
the cylinders to the same oversize. Do not bore only one
cylinder to the
oversize. | |
Install the following
parts by referring to their respective sections.