PIAGGIO B 250 - Page 208

- Prepare the carburettor for adjustment by rotating
the screw 3 turns from the close position.
- Check that the rocking lever control of the accel-
erating pump does not show abnormal wear.
- Check that the end of stroke screw of the rocking
lever protrudes 3.2 mm.
Check that the return spring of the rocking lever is
not loaded.
- Preassemble the spring and rocking lever as
shown in the figure.
- Assemble the rocking lever on the carburettor
keeping the throttle valve open.
- Lock the fixing screw of the rocking lever.
- Make sure that the mechanism works correctly.
Inspecting the valve and needle
Kehin
- Check that the tapered pin of the vacuum valve
does not show wear.
- Check that the depression valve does not show
threads on the external surfaces.
- Check that the vacuum intake hole is not clogged.
- Check that the diaphragm is not damaged or has
hardened, otherwise replacement the whole valve.
- Insert the tapered pin into the vacuum valve
housing.
- Reassemble the vacuum valve on the carburettor
body taking care that the tapered pin is inserted
into the sprayer.
Engine B 125-250
ENG - 208