DAELIM ET-250 Service Manual page 68

Coat some engine oil to inside of cylinder, piston and
piston rings.
Care to be taken when installing piston into cylinder.
Press piston rings in one by one as installation.
Caution
Do not push piston into cylinder forcefully
because piston and piston rings will be damaged.¡C
Install coolant hose onto cylinder.
Install cylinder head (refer to Chapter 6).
Coolant hose