Removing The Piston; Checking The Head And Cylinder - APRILIA Quasar 50 Manual

ENGINE
3
3
- 8 -
00
3.2.3

REMOVING THE PISTON

1
Remove the cylinder, 3.2.2 (REMOVING THE CYLINDER).
Before removing the piston pin retaining ring, cover the crankcase
opening with a clean cloth so as to prevent the ring from falling into the
crankcase; before removing the piston pin, carefully deburr the retaining
ring groove and the adjoining part of the pin insertion hole.
Remove the retaining ring (1).
Extract the piston pin (2).
Remove the piston (3) and the roller cage from its housing in the connecting
rod.
2
3.2.4

CHECKING THE HEAD AND CYLINDER

Decoke the head using a soft rounded scraper, and taking care not to damage
the spark plug thread or scrape the aluminium.
Inspect and decoke the cylinder head combustion chamber.
Check and if necessary restore the planarity of the head to the limit of 0.05
mm. To do so:
- rest a straight edge on the cylinder head and check its planarity using a
thickness gauge.
If the planarity is outside the tolerance range, restore it by rubbing the head
with wetted 400-600 abrasive paper in a figure-of-eight pattern.
The cylinder must be checked in the same way.
Check that the cylinder barrel shows no signs of seizing, wear or scoring.
QUASAR 50-100
Release 00/2003 - 06