Yamaha YZ125(S)/LC, Owner'S Service Manual

Page: 514 / 568

EC719072
Jet needle adjustment
(For USA, CDN, ZA, AUS and NZ)
On the carburetors used in the YZ125, the main
nozzle is a non disassembly type, so it can not
be replaced. Therefore, carburetor setting
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 start-
ing positions.
<Example>
6CHY6-81
Diameter of straight portion
Clip position
Taper angle
In the case of the same number of clip posi-
tion changing from 6CHY6-81 to 6CHY5-81
has the same effect as a lowering of 0.5 clip
position.
A
Difference in straight portion dia.
B
Difference in clip position
a
Reference needle
b
0.5 leaner
7-6
TUN
SETTING
6CHY6-80
6CHY6-81
6CHY6-82
6CHY6-81
6CHY5-81
b
a
B
A
Standard jet needle 6CHY6-81
Diameter of straight
Rich Lean
Clip position
portion
ø2.800 mm (0.1102 in) ø2.810 mm (0.1106 in) ø2.820 mm (0.1110 in)
Rich 1 richer 6CHY6-80-4th groove 6CHY6-81-4th groove 6CHY6-82-4th groove
0.5 richer 6CHY5-80-4th groove 6CHY5-81-4th groove 6CHY5-82-4th groove
STD 6CHY6-80-3rd groove 6CHY6-81-3rd groove 6CHY6-82-3rd groove
0.5 leaner 6CHY5-80-3rd groove 6CHY5-81-3rd groove 6CHY5-82-3rd groove
Lean 1 leaner 6CHY6-80-2nd groove 6CHY6-81-2nd groove 6CHY6-82-2nd groove
5XE-9-30-7A 4/30/03 9:39 AM Page 12