Yamaha YZ125(W)/W1 Owner's Service Manual page 528

Diameter of straight
portion
Clip position
Rich 1 richer
0.5 richer
STD
0.5 leaner
Lean 1 leaner
Rich
ø2.72 mm (0.1071 in) ø2.73 mm (0.1075 in) ø2.74 mm (0.1079 in) ø2.75 mm (0.1083 in) ø2.76 mm (0.1087 in)
6BFY43-72-4 6BFY43-73-4
6BFY44-72-3 6BFY44-73-3
6BFY42-72-4 6BFY42-73-4
6BFY43-72-3 6BFY43-73-3
6BFY44-72-2 6BFY44-73-2
6BFY42-72-3 6BFY42-73-3
6BFY43-72-2 6BFY43-73-2
SETTING
EC719072
Jet needle adjustment
(For EUROPE, AUS, NZ and ZA)
On the carburetors used in the YZ125, the main
nozzle is a non disassembly type, so it can not
be replaced. Therefore,
requires the change of the jet needle.
1. The jet needle setting parts, having the
same taper angle, are available in different
straight portion diameters and in different
taper starting positions.
Standard jet needle
<Example>
6BFY43-74
Diameter of straight portion
Clip position
Taper angle
In the case of the same number of clip posi-
tion, changing
6BFY42-74 has the same effect as a lower-
ing of 0.5-clip position. And in the case of the
same number of clip position, changing from
6BFY43-74 to 6BFY44-74 has the same
effect as a rising of 0.5-clip position.
A Difference in straight portion dia.
B Difference in clip position
a Reference needle
b 0.5 richer
c 0.5 leaner
6BFY43-74-4
6BFY44-74-3
6BFY42-74-4
6BFY43-74-3
6BFY44-74-2
6BFY42-74-3
6BFY43-74-2
7-7
TUN
carburetor
6BFY43-74
from 6BFY43-74
Lean
6BFY43-75-4 6BFY43-76-4
6BFY44-75-3 6BFY44-76-3
6BFY42-75-4 6BFY42-76-4
6BFY43-75-3 6BFY43-76-3
6BFY44-75-2 6BFY44-76-2
6BFY42-75-3 6BFY42-76-3
6BFY43-75-2 6BFY43-76-2
setting
to