Piston Pin, Needle Bearing And Retaining Rings - Rotax 125 MAX DD2 Repair Manual

✔ Check the piston ring locking pin for wear.
✔ Determine the piston diameter with a micrometer,
as shown in Fig. 51. Conditions of measurement:
Room temperature = 20 °C, Measuring position
20 mm from the lower edge of the piston, at right
angles to the piston pin.
✔ Determine the piston clearance. The wear limit
is 0.08 mm.
◆ Note:
If this limit value has been reached,
a piston of the same dimensional
category must be fitted.
◆ Note:
The permissible piston-cylinder
pairings are given in the section on
piston and cylinder sizes, see page
35.
◆ Note:
The piston clearance of a new piston/cylinder pairing should be 0.04 - 0.05 mm.
◆ Note:
On installation of a new piston the piston pin, needle bearing and the retaining rings should
also be replaced.

Piston pin, needle bearing and retaining rings

✔ Inspect the piston pin (Item 4) for wear and
discoloration.
✔ Inspect the needle bearing (Item 5) for cracks,
material erosion and discoloration.
✔ The piston pin retainer rings (Item 3) are replaced
each time a repair is carried out.
The piston (Item 1), piston ring (Item 2) and conrod
(Item 6) have already been subjected to an
inspection, see pages 31 to 34.
Page 34
Repair Manual 125 MAX DD2
Fig. 51
Fig. 52
Issue 01/2006