Piston Wear - Husqvarna K1270 II Workshop Manual

been broken through. Aluminium from the piston can be
removed using emery cloth.
6.8.5 To examine the piston
The bottom of the piston, near the inlet and exhaust
ports, usually shows the largest signs of wear. Examine
the lines made by the manufacturing process. Replace
the piston if the bottom has been worn smooth. A
product with a worn piston is difficult to start because of
the decreased valve function of the piston.
6.8.6 Piston wear tolerances
6.8.6.1 Piston ring play
If the piston ring play is more than 0.006 in./0.15 mm,
the piston ring groove must be measured as set out
below.
44 - Repair and servicing
6.8.6.2 Piston ring groove
If the piston ring groove is larger than 0.06 in./1.6 mm,
the piston must be replaced. Install a complete piston kit
with piston rings, needle bearing and wrist pin.
6.8.6.3 To examine the piston ring for wear
• Put the piston ring in the cylinder with the aid of the
piston. Put it approximately 1 in./2.5 cm from the
bottom of the cylinder. The piston ring distance (A)
must be maximum 0.04 in./1.0 mm.
A

6.9 Piston wear

The cause of engine failure can be hard to find if the
previous operation and service of the product is not
available. Use the following examples for help.
6.9.1 Usual wear
Usual wear is easiest to see on the piston sections that
point at the exhaust and inlet sides. The picture shows
that the piston has been polished to give a bright
surface. The lines from the production can also be seen.
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