Husqvarna 570 Workshop Manual page 45

Faults and causes
Score marks in the piston, fig. 8 (A)
1. Incorrect carburettor setting. Too high maxspeed.
2. Too low octane fuel.
3. Too little, or incorrect oil in the fuel.
Carbon build-up, fig. 8 (B)
1. Incorrect carburettor setting. Too low maxspeed.
2. Too much, or incorrect oil in the fuel.
Piston ring breakage
1. Excessive engine speed.
2. Piston ring worn out.
3. Oversized piston ring groove.
Assembly
Assembly of the piston and cylinder is carried out as
follows:
NOTE!
Exercise care so that dirt and foreign partic-
les do not get into the crankcase.
1. Lubricate the needle bearing and fit it in the
connecting rodʼs little-end.
2. Replace the piston with the arrow facing the exhaust
port. See fig. 9. Slide in the gudgeon pin and fit the
circlips.
3. Fit the intake manifold on the cylinder before
fitting cylinder to crank case. Apply grease to the
sealing surface. Tighten the 3 screws. The square
nuts (B) can be changed if damaged. Connect
impuls hose and fit into possition. See fig. 10.
4. Fit the decompression valve (B). See fig. 12.
Tighten it to 15 Nm.
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 with two
stroke oil.
7. Compress the piston ring, either by hand or with tool
502 50 70-01. See fig. 11. Carefully fit on the
cylinder.
PISTON and CYLINDER
A
Fig. 8
Fig. 9
B
Ax3
Fig. 10
Fig. 11
B
English – 45