Cylinder - Nikasil Coating; Checking/Measuring The Cylinder; Checking/Measuring The Piston - Husqvarna FC 250 2015 Repair Manual

17 ENGINE
17.4.13 Cylinder - Nikasil
--------·
�
'
17.4.14

Checking/measuring the cylinder

17.4.15

Checking/measuring the piston

•
--♦-
'
,-
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,'
. .
----- -
coating
®
® is a surface protection layer for a coating procedure developed by Mahle.
Nikasil
The name is derived from the two materials used in this procedure - a layer of nickel
into which is embedded the particularly hard silicone carbide.
The most important advantages of the
tivity, resulting in much improved performance, low wear, and a lightweight cylinder.
306757-10
-
Check the cylinder bearing surface for damage.
If the cylinder bearing surface is damaged:
-
Change the cylinder and piston.
-
Measure the cylinder diameter at several locations on the
a micrometer to identify oval wear.
Guideline
Cylinder - drill hole diameter
Size I
Size II
• Info
I
The cylinder size
-
Using a straightedge and the special tool, check the sealing area of the cylinder
head for distortion.
I
Feeler gauge (590290411 00)
Cylinder/cylinder head - distortion of
sealing area
If the measured value does not meet specifications:
-
Change the cylinder.
305004-10
-
Use the special tool to measure clearance
groove.
I Guideline
Piston ring - groove clearance
I
Feeler gauge (590290411 00)
If play
-
Change the piston and piston rings.
-
400995-10
Check/measure the cylinder.
-
Check the piston sliding surface for damage.
If the piston sliding surface is damaged:
-
Replace the piston and, if necessary, the cylinder.
-
Check that the piston rings move easily in the piston ring grooves.
If the piston ring is stiff:
.
-
Clean the piston ring groove.
305017-10
Nikasil
O
is marked on the cylinder collar.
(� p. 226)
(� p. 226)
6)
is larger than the specified value:
(�
Tip
An old piston ring can be used to clean the piston ring groove.
® coating are very good heat conduc­
0-
and 0-axes
78.000 ... 78.012 mm (3.07086 ...
3.07133 in)
78.012 ... 78.025 mm (3.07133 ...
3.07184 in)
s; 0.10 mm (::. 0.0039 in)
6)
of the piston rings in the piston ring
I
s; 0.08 mm (::. 0.0031 in)
p. 148)
148
using