2006 YAMAHA YZ450F ESP

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Examples of carburetor setting depending on symptom
This should be taken simply for an example. It is necessary to set the carburetor while checking
the operating conditions of the engine.
Symptom Setting Checking
At full throttle
Hard breathing
Shearing noise
Whitish spark plug
Lean mixtureIncrease main jet calibration no.
(Gradually)
Discoloration of spark plug
→
If tan color, it is in good condition.
If cannot be corrected:
Clogged float valve seat
Clogged fuel hose
Clogged fuel cock
Check that the accelerator pump
operates smoothly.
At full throttle
Speed pick-up stops
Slow speed pick-up
Slow response
Sooty spark plug
Rich mixtureDecrease main jet calibration no.
(Gradually)
Discoloration of spark plug
→
If tan color, it is in good condition.
If cannot be corrected:
Clogged air cleaner
Fuel overflow from carburetor
Lean mixture Lower jet needle clip position.
(1 groove down)
The clip position is the jet needle
groove on which the clip is installed.
The positions are numbered from the
top.
Check that the accelerator pump oper-
ates smoothly (except for rich mixture
symptom). Rich mixture Raise jet needle clip position.
(1 groove up)
1/4 ~ 3/4 throttle
Hard breathing
Lack of speedLower jet needle clip position.
(1 groove down)
1/4 ~ 1/2 throttle
Slow speed pick-up
Poor accelerationRaise jet needle clip position.
(1 groove up)
Closed to 1/4 throttle
Hard breathing
Speed downUse jet needle with a smaller diame-
ter.Slow-speed-circuit passage
Clogged
→ Clean.
Overflow from carburetor
Closed to 1/4 throttle
Poor accelerationUse jet needle with a larger diameter.
Raise jet needle clip position. (1
groove up)
Poor response in the low to
intermediate speedsRaise jet needle clip position.
If this has no effect, lower the jet nee-
dle clip position.
Poor response when throt-
tle is opened quicklyCheck overall settings.
Use main jet with a lower calibration
no.
Raise jet needle clip position.
(1 groove up)
If these have no effect, use a main jet
with a higher calibration no. and lower
the jet needle clip position.Check air cleaner for fouling.
Check that the accelerator pump
operates smoothly.
Jet needleClip
Groove 7 Groove 6
Groove 5
Groove 4
Groove 3
Groove 2
Groove 1
Leaner
↑
(Standard)
↓
Richer
*
SETTING

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EC72P000
Front fork setting parts
•Front fork spring 1
* For EUROPE
NOTE:
The I.D. mark (slits) a is proved on the end of
the spring.TYPESPRING
RATESPRING
PART NUMBERI.D.
MARK
(slits)
SOFT0.398
0.408
0.418
0.428
0.438
0.4491C3-23141-A0
1C3-23141-B0
1C3-23141-C0
1C3-23141-D0
1C3-23141-E0
1C3-23141-F0I
II
III
IIII
IIIII
I-I
*STD 0.459 2S2-23141-M0–
STD 0.469 2S2-23141-L0–
STIFF 0.479 1C3-23141-J0 I-IIII
EC72B000
Rear suspension setting
The rear suspension setting should be made
depending on the rider’s feeling of an actual
run and the circuit conditions.
The rear suspension setting includes the fol-
lowing two factors:
1. Setting of spring preload
•Change the set length of the spring.
•Change the spring.
2. Setting of damping force
•Change the rebound damping.
•Change the compression damping.
SETTING

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TUNSETTING
EC72Q000
Rear shock absorber setting parts
•Rear shock spring 1
[Equal-pitch titanium spring]
[Equal-pitch steel spring]
[Unequal-pitch steel spring]
CAUTION:
Install the spring seat
2 to the titanium
spring.
NOTE:
•The unequal-pitch spring is softer in initial
characteristic than the equal-pitch spring and
is difficult to bottom out under full compres-
sion.
•The I.D. mark a is marked at the end of the
spring.
•Spring specification varies according to the
color and quantity of I.D. marks.
TYPESPRING
RATESPRING
PART NUMBERI.D.
MARKSPRING
FREE
LENGTH
(approx.)
SOFT4.5
4.7
4.9
5.1
5.31C3-22212-00
1C3-22212-10
1C3-22212-20
1C3-22212-30
1C3-22212-40Green
Red
Black
Blue
Yellow265
265
265
265
275
STD 5.5 1C3-22212-50 Pink 275
STIFF 5.7 1C3-22212-60 White 275
TYPESPRING
RATESPRING
PART NUMBERI.D.
MARK/
Q’TYSPRING
FREE
LENGTH
4.3 5UN-22212-00 Brown/1 260
TYPESPRING
RATE
(approx.)SPRING
PART NUMBERI.D.
MARK/
Q’TYSPRING
FREE
LENGTH
SOFT
STIFF4.5
4.7
4.9
5.1
5.3
5.5
5.75UN-22212-A0
5UN-22212-B0
5UN-22212-C0
5UN-22212-D0
5UN-22212-E0
5UN-22212-F0
5UN-22212-G0Green/2
Red/2
Black/2
Blue/2
Yellow/2
Pink/2
White/2275
275
275
275
275
275
275
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Einstellbereich (Federlänge)
[Titanfeder]
[Stahlfeder]
UNGESPANNTE LÄNGE EINSTELLBEREICH b
Circa 265 mm (10,43 in)Eine Kennmarkierung
245,5–263,5 mm
(9,67–10,37 in)
Zwei Kennmarkierungen
251,5–269,5 mm
(9,90–10,61 in)
Drei Kennmarkierungen
243,0–261,0 mm
(9,57–10,28 in)
Circa 275 mm (10,83 in)Eine Kennmarkierung
255,5–273,5 mm
(10,06–10,77 in)
Zwei Kennmarkierungen
261,5–279,5 mm
(10,30–11,00 in)
Drei Kennmarkierungen
253,0–271,0 mm
(9,96–10,67 mm)
UNGESPANNTE LÄNGE EINSTELLBEREICH b
260 mm (10,24 in)240,5–258,5 mm
(9,47–10,18 in)
275 mm (10,83 in)255,5–273,5 mm
(10,06–10,77 in)
REGLAGE
EINSTELLUNG
Plage de réglage (longueur du ressort)
[Ressort en titane]
[Ressort acier]
LONGUEUR LIBRE DU
RESSORTPLAGE DE REGLAGE b

Approx. 265 mm (10,43 in)Un seul repère d’identifica-
tion
245,5 à 263,5 mm
(9,67 à 10,37 in)
Deux repères d’identifica-
tion
251,5 à 269,5 mm
(9,90 à 10,61 in)
Trois repères d’identifica-
tion
243,0 à 261,0 mm
(9,57 à 10,28 in)
Approx. 275 mm (10,83 in)Un seul repère d’identifica-
tion
255,5 à 273,5 mm
(10,06 à 10,77 in)
Deux repères d’identifica-
tion
261,5 à 279,5 mm
(10,30 à 11,00 in)
Trois repères d’identifica-
tion
253,0 à 271,0 mm
(9,96 à 10,67 in)
LONGUEUR LIBRE DU
RESSORTPLAGE DE REGLAGE b

260 mm (10,24 in)240,5 à 258,5 mm
(9,47 à 10,18 in)
275 mm (10,83 in)255,5 à 273,5 mm
(10,06 à 10,77 in)
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