VESPA 633844 IT Service Manual page 140

Engine
Locking torques (N*m)
Timing chain tensioner support screw 11 ÷ 13
- Refit the lower timing chain sprocket wheel on the
crankshaft, with the chamfer facing the insertion
side.
- Loop the timing chain around the sprocket on the
crankshaft.
- Fit the chain tensioner slider from the cylinder
head side.
- Fit the spacer and the screw fastener.
- Tighten the screws to the prescribed torque.
- Fit the pins and rocker arms.
- Lubricate the two rocking levers through the
holes at the top.
- Lubricate the 2 bearings and insert the cam shaft
in the cylinder head with the cams corresponding
to the rockers.
- Insert the retention plate and tighten the two
screws shown in the figure to the prescribed tor-
que.
- Refit the spacer on the cam shaft.
- Rotate the engine so that the piston is at top dead
centre, using the reference marks on the flywheel
and the crankcase.
- Holding this position insert the chain on the cam-
shaft control pulley.
- Insert the pulley on the cam shaft while keeping
the reference 4V in correspondence with the ref-
erence mark on the head.
- Fit the counterweight and tighten the fixing screw
to the prescribed torque.
ENG - 46
Vespa GTV 250 i.e.