Checking The Revs-Timing Sensor Air Gap - PIAGGIO 500 cc Service Manual

Thermal unit and timing system
- Turn the engine. Move the reference marks to the
upper position as shown in the figure (intake end)
- Fit the valve lifter counterweight stop bell.
- Tighten the fixing screw to the prescribed torque,
using LOCTITE 242.
N.B.: The bell timing is given by the head of the
counterweight fixing screw
- Check that the decompression counterweight is free
and the returning action of the spring.
Tightening torque:
Valve lifter counterweight stop bell
fixing screws: 30 - 35 N·m
- Position the engine with the valve play adjustment
timing reference marks aligned with the head
- Check the valve-equalizer play by means of a thick-
ness gauge
Prescribed play: intake 0,20 mm 0.15mm
(cold engine)
exhaust 0,20 mm
(cold engine)
- If different values are measured, adjust by unloosing
the check nut and by acting on the register with a tool
as shown in the figure.

Checking the revs-timing sensor air gap

- Align one tooth of the phonic wheel with the revs-
timing sensor.
- Check the air gap by means of a feeler.
Standard air gap: from 0.20 to 0.70 mm
- Perform the check in 3-4 points.
0.15mm
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