Yamaha 2002 YB50, Service Manual

Page: 87 / 161

MOT
ASSEMBLY AND ADJUSTMENT OF ENGINE
4-36
PISTON AND PISTON PIN
1. Apply:
• Engine oil
(in the crankshaft bearing, big end bea-
ring, small end bearing, piston pin, piston
ring grooves and piston skirt areas.)
2. Install:
• Reed valve gasket
• Reed valve
• Carburettor gasket
3. Install:
• Small end bearing
• Piston
• Piston pin
• Piston circlips
NOTE:
• The arrow of the piston should point to
the exhaust side.
• Before installing the piston circlip, cover the
crankcase with a towel or clean cloth so
that the circlip and other materials do not
accidentally fall into the crankcase.
• Always use new piston circlips.
CYLINDER AND CYLINDER HEAD
1. Install:
• Cylinder gasket (Use a new gasket)
2. Check:
• Piston rings
NOTE:
• Ensure that the ends of the rings are
correctly coupled around the centring devi-
ces
on the piston grooves.
• Check that the manufacturers symbols or
numbers printed on the rings are on the
upper side of same.
Carburettor gasket
0.9 m • kg