Yamaha pw80 - Manual (Page 33)

b. Adjustment
CAUTION:
Check the needle valve and valve seat for
wear before adjustment.
Make the adjustment by bending the tang
on the float arm.
2. Jet needle
The mid-range air/fuel supply is affected
by the position of the needle in the nee­
dle jet. If it is necessary to alter the mid­
range air/fuel mixture characteristics of
the machine, the jet needle position may
be changed. Move the jet needle up for
a leaner condition or toward the bottom
position for a richer condition.
Jet needle type: 3E3
Clip position: No. 3 Groove
Inspection
1. Inspect rubber intake manifold for signs
of weathering, checking or other deterio­
ration.
2. Inspect reed petals for signs of fatigue and
cracks. Reed petals should fit flush or
nearly flush against neoprene seats. If in
doubt as to sealing ability, apply suction
to carburetor side of assembly. Leakage
should be slight to moderate.
L The valve stopper controls the movement
of the valve. Check the valve stopper
height.
Valve stopper height (a):
7.4~7.8 mm (0.291 -0.307 in)
If the valve stopper height is not within
specification, replace the valve stopper.
tolerance, replace reed valve.
Reed valve bending limit:
0.2 mm (0.008 in)
5. Manifold:
Check the distortion of manifold surface.
If the distortion is out of limit, resurface
it on the #600 wet sandpaper.
Distortion limit: 0.1 mm (0.004 in)
-21-