Inspecting The Piston Rings; Removing The Piston - Derbi GP1 50 cc Workshop Manual

I I
NSPECTING THE PISTON RINGS NSPECTING THE PISTON RINGS
- Alternatively insert the two piston rings inside the cylinder.
- Insert the piston rings in the direction orthogonal to the
cylinder axis, using the piston to push them through.
- Measure the rings gap using a feeler gauge as shown in
the picture.
- If the measured values exceed those shown inthe table,
proceed by replacing the rings.
R R
EMOVING THE PISTON EMOVING THE PISTON
- Position the piston ring inside part 1 with its opening coin-
ciding with the arrow shown on the tool.
- Push part 2 through part 1 as far as it will go and hence
extract part 2.
- Insert part 3 inside part 1, position the assembly in the pis-
ton ring housing and push part 3 home.
N.B.
REFIT THE REMAINING COMPONENTS FOLLOWING THE
OPERATIONS FOR THEIR REMOVAL IN THE REVERSE ORDER.
Specific tooling
020166y Piston rings fixing tool
Locking torques (N*m)
Cylinder head lock nuts 10-11 N-m
- Use new split rings for the wrist pin.
- Replace the cylinder base gasket with a new one.
- Before proceeding with the reassembly carefully clean all
surfaces.
- Lubricate components with two-stroke oil when refitting
piston and cylinder.
CAUTION
POSITION THE ARROW STAMPED ON THE TOP OF THE PIS-
TON TOWARDS THE EXHAUST PORT. THE WRIST PIN SPLIT
RINGS MUST BE POSITIONED ON THE PISTON USING THE
SPECIAL TOOL.
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