Install the oil ring expander [A] in the piston oil ring groove
so that the expander ends [B] butt together, never overlap.
Install the upper and lower steel rails. There is no UP or
DOWN to the rails. They can be installed either way.
Install the top ring [A] so that the "N" mark [B] faces up.
Install the second ring [C] so that the "N" mark [D] faces
If new piston or cylinder is used, check piston to cylin-
der clearance (see Specifications), and use new piston
Position each piston ring so that the openings in the top
ring and oil ring steel rails are facing forwards, and the
second ring and oil ring expander openings face the rear.
The openings of the oil ring steel rails must be about 30°
∼ 40° of angle from the opening of the top ring.
[A] Top Ring
[B] Second Ring
[C] Oil Ring Steel Rails
The arrow on the top of the piston must point toward the
front of the engine (EN500-C1 ∼ C9 Models).
The circle mark on the top of the piston must point toward
the front of the engine (EN500-C10 ∼).
When installing a piston pin snap ring, compress it only
enough to install it and no more.
Do not reuse snap rings, as removal weakens and
deforms them. They could fall out and score the
[D] Oil Ring Expander
ENGINE TOP END 4-31