Yamaha YZ450F(T), Owner'S Service Manual

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T U N
Jet needle adjustment
The jet needle is adjusted by changing it.
The jet needle setting parts, having the same
taper angle, are available in different straight
portion diameters and in different taper starting
positions.
<Example>
NFLR - 4
Clip position
Diameter
a
of straight portion
b
Reference needle
c
0.5 richer
Changing from NFLR-4 to NFPR-4 has the
same effect as a rising of 0.5 clip position.
Standard jet needle NFLR
b
c
NFPR-4
NFLR-4
Diameter of straight portion
Clip position
Rich Lean
N P Q R S T U
Rich
Lean
1 richer NFLN-5 NFLP-5 NFLQ-5 NFLR-5 NFLS-5 NFLT-5 NFLU-5
0.5 richer NFPN-4 NFPP-4 NFPQ-4 NFPR-4 NFPS-4 NFPT-4 NFPU-4
STD NFLN-4 NFLP-4 NFLQ-4 NFLR-4 NFLS-4 NFLT-4 NFLU-4
0.5 leaner NFPN-3 NFPP-3 NFPQ-3 NFPR-3 NFPS-3 NFPT-3 NFPU-3
1 leaner NFLN-3 NFLP-3 NFLQ-3 NFLR-3 NFLS-3 NFLT-3 NFLU-3
SETTING