Rotax 125 MAX DD2 - Cylinder; Piston and Cylinder Sizing

Repair Manual 125 MAX DD2
Page 35 Issue 01/2006
Cylinder
➩ Remove lime deposits from the water cooling
jacket of the cylinder (Item 1).
➩ Clean the exhaust gas and slider duct of
combustion residues.
➩ Clean the o-ring groove (Item 3).
✔ Inspect the threads (Item 2).
✔ Inspect the sealing surfaces, they must be clean
and smooth.
✔ Measure the wear of the cylinder wall (Item 4),
as well as the conicity and the ovality. The
measurement is made in the area between the
T.D.C. position of the piston ring and 3 mm above
the upper edge of the outlet. The wear limit is
0.03 mm, respectively, above the installation dimension.
✔ Now measure the cylinder diameter 10 mm below the upper edge of the cylinder. This dimension
dictates the selection of the matching piston and piston rings. If the dimension reaches the limit value
of 54.035 mm, the cylinder must be replaced.
Piston and cylinder sizing
When installing a new piston and/or cylinder check the appropriate size category from the table.
◆ Note: A new piston has the size classification stamped on the piston skirt.
◆ Note: On new cylinders the size classification is stamped on the top.
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