TOP perfomances 9928300 Mode D'emploi page 15

• Piston-cylinder assy assembly
WARNING: Cover the casing opening with a clean cloth to
prevent the gudgeon pin circlip from accidentally falling into it.
– Lubricate the piston gudgeon pin and the con-rod small end with
engine oil.
– 4V VERSION: Fit one base gasket 0.4 mm thick and the two
centring dowels.
– 3V iGET VERSION: Fit both base gaskets supplied (2x 0.4
mm thick).
– Position the piston on the connecting rod and insert the new
gudgeon pin. Make sure that the arrow (or the symbol) punched
on the piston crown is faces the exhaust side.
– Fit the second gudgeon pin circlip and check that it is correctly
positioned in its seat.
– Recheck that the piston rings openings are positioned as shown
in Fig. 4.
– Lubricate piston, piston rings and cylinder.
– Insert the new TOP cylinder by pressing the piston rings (with
a hand or by means of compression tool) by passing the timing
chain through the suitable cylinder cavity, and then push the
cylinder fully against the casing.
– Fit the chain guide sliding block by positioning it in the proper
seat.
– Fit the two centring dowels and the new head gasket.
– Position the head on the cylinder and make use of an iron wire
to pass the timing chain through the proper head cavity.
– Slightly oil the four bolt threads (M6) with engine oil.
– Tighten the four head M6 nuts in a crossed pattern and with
tightening torque of 6 ÷ 7 Nm +90° +90°.
– Tighten the two side screws (M6) securing head to crankcase
with tightening torque of 8 ÷ 10 Nm.
– Bring the engine to the top dead centre in the compression
phase.
– 4V VERSION: Align the second tooth on the fl ywheel with the
tooth of the manifold (pick up) by turn the crankshaft clockwise
using the generator rotor nut (Fig. 2).
– 3V iGET VERSION: Bring the piston to the top dead centre
(TDC) using the specifi c Piaggio tool or, as an alternative,
search the position using a dial gauge, taking care to mark a
reference on rotor and crankcase (Fig. 3).
– Fit the timing chain on the gear.
– Insert the gear on the camshaft and align its reference point (Fig.
1) with the reference on the head and tighten with a tightening
torque of 12 ÷ 14 Nm (M6 screw) or 18 ÷ 20 Nm (M8 screw).
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