Yamaha YZ450F Fahrer- Und Wartungshandbuch Seite 614

c
b
Diameter of straight portion
Clip position
Rich 1 richer
0.5 richer
STD
0.5 leaner
Lean 1 leaner
NFPR-4
NFLR-4
Rich
N P
NFLN-5 NFLP-5
NFPN-4 NFPP-4
NFLN-4 NFLP-4
NFPN-3 NFPP-3
NFLN-3 NFLP-3
SETTING
Jet needle adjustment
The jet needle is adjusted by changing it.
Standard jet needle
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 leaner
Changing from NFLR-4 to NFPR-4 has the
same effect as a rising of 0.5 clip position.
Q R
NFLQ-5 NFLR-5
NFPQ-4 NFPR-4
NFLQ-4 NFLR-4
NFPQ-3 NFPR-3
NFLQ-3 NFLR-3
Effects of changing the jet needle
(reference)
(Diameter of the straight portion)
Changing the diameter of the straight portion
adjusts the air-fuel mixture when the throttle is
1/8 to 1/4 open.
È
1/4
È Idle É Fully open
7 - 7
T U N
NFLR
S T
NFLS-5 NFLT-5
NFPS-4 NFPT-4
NFLS-4 NFLT-4
NFPS-3 NFPT-3
NFLS-3 NFLT-3
1/2 3/4
Q
S
Lean
U
NFLU-5
NFPU-4
NFLU-4
NFPU-3
NFLU-3
É
+10%
R
–10%