Specifications

– Rotate the carburettor, loosen the three screws and remove
the accelerating pump cover.
NOTE: When removing the cover, ensure that the spring
and the seal rings are not lost.
– Remove the two seal rings, the spring and the diaphragm from
the pump casing.
– Remove the float chamber screws and detach the float cham-
ber.
– Remove float pin 1 and remove the float together with the nee-
dle valve.
– Remove main jet 2.
– Loosen screw 3 and, using a pair of pliers, carefully remove
the float needle valve support from the carburettor.
– Unscrew idling jet 4, starting jet 5 and nozzle 6.
– Tighten mixture adjusting screw 7 until it stops, taking note of
the screw turns.
– Unscrew the mixture adjusting screw and remove it together
with the spring, washer and O-ring.
NOTE: As a rule, the spring, the washer and the O-ring remain
in the hole. These parts can be removed with a jet of com-
pressed air.
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Workshop manual RR 4T - 400 - 450 - 525
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