Checking Valve Springs; Checking Valve Spring Seat; Checking The Cylinder Head - Husqvarna FS 450 2018 Repair Manual

17 ENGINE
17.4.30
17.4.31
17.4.32
208

Checking valve springs

304678-10

Checking valve spring seat

304679-10

Checking the cylinder head

310049-10
-
Check the valve springs for breakage and wear (visual
check).
If the valve spring is broken or worn:
-
Change the valve spring.
-
Measure the length of the valve springs.
Valve spring
Minimum length, intake
(without valve spring
seat)
Valve spring
Minimum length,
exhaust (without valve
spring seat)
If the measured value does not meet specifications:
-
Change the valve spring.
-
Check the valve spring seat for breakage and wear (visual
check).
If the valve spring seat is broken or worn:
-
Change the valve spring seat.
-
Measure the thickness of the valve spring seat.
Valve spring
Valve spring seat
If the measured value does not meet specifications:
-
Change the valve spring seat.
-
Check exhaust valve guides
I Limit plug gauge (59029026006)
If the special tool is easy to insert into the valve guide:
-
Change the valve guide and valve.
-
Check intake valve guides @ using the special tool.
I Limit plug gauge (59029026006)
If the special tool is easy to insert into the valve guide:
-
Change the valve guide and valve.
-
Check the sealing area of the spark plug thread and the valve
seats for damage and tearing.
If there is damage or cracking:
-
Change the cylinder head.
40. 7 mm (1 .602 in)
40. 7 mm (1 .602 in)
1.9 ... 2.1 mm (0.075 ...
1
0.083 in)
O
using the special tool.
(8 p. 309)
(8 p. 309)