Husqvarna 131RB Workshop Manual page 57

Other damages on the cylinder/piston
Broken cooling fins, damaged threads or broken bolts by
the exhaust port.
Score marks in the cylinder bore, especially by the ex-
haust port.
Surface layer in the cylinder bore worn out, especially at
the top of the cylinder.
The piston shows signs of seizure score marks.
The piston ring is burned in its groove.
Bolts much too tight in the metal material.
8.13.5 Wear tolerance
8.13.5.1 Cylinder bore
Examine the cylinder bore. Replace the cylinder bore if
the surface layer is worn and aluminum shows.
8.13.5.2 Piston ring space
Measure the piston ring space. The space must not be
larger than 1.0 mm with the piston ring in the lower part
627 - 002 - 23.04.2018
Procedure
Repair the threads with a thread repair kit. Replace the
cylinder if it cannot be repaired.
Polish the damaged area with an emery cloth of fine
grade to remove the coating of aluminum. Replace the
piston and cylinder if the score marks are large.
Replace the cylinder and piston.
Carefully polish the damaged area with an emery cloth of
fine grade. Before the piston is attached to the cylinder,
the piston must be polished as above. Replace the cylin-
der and piston if the score marks are large.
Carefully loosen the piston rings and clean the groove
before attaching them. Carbon particles in the groove de-
crease the heat supply between the piston and cylinder.
Be careful with the lower edge of the piston ring groove. If
this is damaged, or if there are carbon particles, the com-
pression pressure can leak through. To examine the wear
on the piston ring, put it in the lower part of the cylinder
bore.
Put an applicable punch on the bolt head and hit the
punch hard with a hammer. If the bolt does not loosen, do
the procedure again.
of the cylinder. Replace the cylinder bore if the space is
more than 1.0 mm.
Repair instructions - 57