Hitachi NT 65GB Technical Data And Service Manual page 40

(b) Reassembly
Conduct reassembly by reversing the disassembly procedure. Note the following points:
• Set the Muffler [49] at the concave section between the claws of the Buffer Cover [48].
• Drop the Piston Bumper [28] into Cylinder Ass'y (A) [104A] by facing its stepped side inward
and using the handle of a hammer to push it in until it passes through the stopper portion. You
feel a click when the Piston Bumper [28] passes through the stopper portion (Fig. 33).
• Apply designated oil to the inside of Cylinder Ass'y (A) [104A] and the piston ring groove on
the outside of Cylinder Ass'y (A) [104A] as described in Section 10-1.
• Mount the two Piston Ring (A) [26] to the Piston [27], and be careful not to deform the rings.
• Be careful about the following when mounting the Piston [27] to Cylinder Ass'y (A) [104A].
(1) Position each split of the two Piston Ring (A) [26] at an angle of 90 degrees relative to the
exhaust port aligning both splits at 180 degree opposite positions (Fig. 34).
(2) Confirm that the tip of the driver blade can be seen in the outlet. The Piston [27] cannot be
mounted if the tip of the driver blade contacts the Piston Bumper [28] or the bottom of the
cylinder.
(3) Face the grooved side of the driver blade toward the direction shown in Fig. 34.
Buffer Cover [48]
Muffler [49]
Fig. 33
-37-
Claws
Handle of a hammer
Cylinder Ass'y (A) [104A]
Stopper portion
Piston Bumper [28]