Husqvarna 390XP Workshop Manual page 44

Piston and cylinder
17.3 Assembly
To assemble the piston and cylinder.
1. Lubricate the needle bearing and fit it in the
connecting rod's smallest end.
2. Replace the piston with the arrow facing the exhaust
port. See fig. 8. Slide in the gudgeon pin and fit the
circlip.
3. Fit the intake manifold on the cylinder. The clamp bolt
should be upwards. See fig. 9.
4. Fit the decompression valve (D). See fig. 11. Tighten
the bolt with correct torque (Refer to "4 Service data"
on page 10).
5. Fit the gasket on the cylinder base. Press it up so
that it fastens on the sleeve of the cylinder.
6. Oil in the piston ring and sides of the piston.
7. Compress the piston ring (See fig. 10), either by
hand or with special tool (Refer to "3 Service tools"
on page 8). Carefully fit on the cylinder.
8. Install the cylinder base gasket with the four bolts
(See fig 11 pos. C) and tighten them alternately (See
fig. 11) with correct torque (See Service Data).
9. Fit the anti-vibration spring (B) on the cylinder. See
fig. 11. Tighten the bolt with correct torque (See
Service Data).
10. Insert the spark plug and do a pressure test. Refer to
the Leakage testing chapter.
Assemble the following parts:
• Muffler.
• Carburettor.
• Cylinder cover. See the Operators Manual.
11. If a new piston and/or cylinder is installed in the
chainsaw should be run-in for 3-4 hours with the
carburettor set at its basic settings (H=1/4 and L=1/4
turn). See carburettor settings.
44 - English
Fig. 8
Fig. 8
Fig. 8
Fig. 8
Fig. 9
Fig. 9
Fig. 9
Fig. 9
Fig. 10
Fig. 10
Fig. 10 Fig. 10
C
C
C
C
Fig. 11
Fig. 11
Fig. 11
Fig. 11
D
D
D
D
B
B
B
B
A
A
A