Choke valves
Ensure that choke knob piston 1 presents no deep scoring or
residues.
Checking the accelerating pump
Check that the diaphragm is not cracked or porous.
Check that the gaskets are not damaged.
Ensure that holes 2 are clear.
Checking the jet needle
Ensure that the jet needle is not bent or worn.
Checking the float needle valve
Check to see if the sealing surface of the needle valve presents
any dimples. There should be no dirt between the valve seat
and the float needle.
Checking the throttle valve
Throttle valve rollers 3 should rotate easily and have no flat ar-
eas. Check that throttle valve plate 4 is not damaged.
1
2
2
3 4
8
Workshop manual RR 4T - 400 - 450 - 525