Yamaha pw80 - Manual (Page 35)

NOTE: _________________________
Break each nut loose (1/4 turn) prior to remov­
ing.
3. With the piston at top dead center, raise
the cylinder until the cylinder skirts clear
crankcase. Stuff a clean shop rag into
crankcase cavity, around rod, to prevent
dirt and other foreign particles from enter­
ing. Remove cylinder.
4. Remove the piston pin clip from the
piston. Push the piston pin out from op­
posite side. Remove the piston.
NOTE: ------------------------------------------
If the pin hangs up, use a piston pin puller. Do
not hammer on pin as damage to rod, piston
and bearing will result.
Maintenance
Cylinder head
1. Using a rounded scraper, remove car­
bon deposits from combustion chamber.
Take care to avoid damaging the spark
plug threads. Do not use a sharp instru­
ment. Avoid scratching the metal sur­
face.
2. Place the head on a surface plate. There
should be no warpage. Correct by resur­
facing. Place 400 ~ 600 grit wet emery
sandpaper on surface plate and re-sur­
face head using a figure-eight sanding
pattern. Rotate head several times to
avoid removing too much material from
one side.
3. Clean the spark plug gasket mating sur­
face throughly.
Cylinder
1. Using a rounded scraper, remove carbon
deposits from exhaust port.
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