Husqvarna T540 XP Workshop Manual page 55

Cleaning and checking
Clean all parts, and scrape off all gasket remains
and soot from the following components:
• The piston crown
• Top of the cylinder bore (inside)
• The cylinder exhaust port
• The base of the cylinder and/or crankcase
Check the following:
• That the cylinder's surface coating is not worn.
Especially the upper part of the cylinder.
• That the cylinder does not have any chafe or
cutting marks.
• That the piston is free from cutting marks.
Minor scratches can be polished off using fine
emery paper.
• That the piston ring is not welded to its track.
• Remove the piston ring from the piston to
measure the wear. Use the base of the piston
to push the piston ring down into the cylinder.
The opening in the ring must not exceed 1 mm.
Put the piston ring back into the piston slot
and make sure it is the right way around. See
Figure 80.
Faults and causes
Score marks on the piston (A).
1. Leakage, check not carried out.
2. Too low octane rating in the petrol.
3. Too little or incorrect oil in the fuel.
Carbon deposits (B)
1. Too much or incorrect oil in the fuel.
Piston ring breakage
1. Piston ring worn out.
2. Oversized piston ring groove.
Fig 80
Fig 81
Repair instructions
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