Jet Needle Adjustment - Yamaha YZ125N1 Service Manual

Diameter of straight
portion
Clip position
Rich 1 richer
0.5 richer
STD
0.5 leaner
Lean 1 leaner
6BGK9-74
6BGK9-75
6BGK9-76
6BGK10-75
6BGK9-75
Rich
ø2.740 mm (0.1079 in)
6BGK9-74-4th groove
6BGK10-74-3rd groove
6BGK9-74-3rd groove
6BGK10-74-2nd groove
6BGK9-74-2nd groove
7-6
SETTING
EC719071

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,
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.
Standard jet needle
<Example>
6BGK9-75
Diameter of straight portion
Clip position
Taper angle
Changing from 6BGK9-75 to 6BGK10-75
has the same effect as a raise of 0.5 clip
position.
A Difference in straight portion dia.
B Difference in clip position
a 0.5 richer
b Reference needle
ø2.750 mm (0.1083 in)
6BGK9-75-4th groove
6BGK10-75-3rd groove
6BGK9-75-3rd groove
6BGK10-75-2nd groove
6BGK9-75-2nd groove
TUN
carburetor setting
6BGK9-75
Lean
ø2.760 mm (0.1087 in)
6BGK9-76-4th groove
6BGK10-76-3rd groove
6BGK9-76-3rd groove
6BGK10-76-2nd groove
6BGK9-76-2nd groove