2003 YAMAHA WR 450F kickstarter maintenance

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GEN
INFO
STARTING AND BREAK-IN
STARTING AND BREAK-IN
WARNING
Never start or run the engine in a closed
area. The exhaust fumes are poisonous;
they can cause loss of consciousness and
death in a very short time. Always operate
the machine in a well-ventilated area.
CAUTION:
The carburetor on this machine has a
built-in accelerator pump. Therefore,
when starting the engine, do not operate
the throttle or the spark plug will foul.
Unlike a two-stroke engine, this engine
cannot be kick started when the throttle is
open because the kickstarter may kick
back. Also, if the throttle is open the air/
fuel mixture may be too lean for the
engine to start.
Before starting the machine, perform the
checks in the pre-operation check list.
AIR FILTER MAINTENANCE
According to “AIR FILTER CLEANING” section
in the CHAPTER 3, apply the foam-air-filter oil
or its equivalent to the element. (Excess oil in
the element may adversely affect engine start-
ing.)
STARTING A COLD ENGINE
NOTE:
This model is equipped with an ignition circuit
cut-off system. The engine can be started
under the following conditions.
When the transmission is in neutral.
When the clutch is disengaged with the
transmission in any position. However, it is
recommended to shift into neutral before
starting the engine.
1. Inspect the coolant level.
2. Turn the fuel cock to “ON”.
3. Push the main switch to “ON”.
4. Shift the transmission into neutral.
5. Fully open the cold starter knob 1.
6. Start the engine by pushing the start
switch or by kicking the kickstarter.

SPEC

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MAINTENANCE SPECIFICATIONS
Clutch:
Friction plate thickness 2.92 ~ 3.08 mm
(0.115 ~ 0.121 in)2.8 mm
(0.110 in)
Quantity 9 ----
Clutch plate thickness 1.1 ~ 1.3 mm (0.043 ~ 0.051 in) ----
Quantity 8 ----
Warp limit ---- 0.1 mm
(0.004 in)
Clutch spring free length 48.4 mm (1.91 in) 47.4 mm
(1.87 in)
Quantity 6 ----
Clutch housing thrust clearance 0.10 ~ 0.35 mm
(0.0039 ~ 0.0138 in)----
Clutch housing radial clearance 0.010 ~ 0.044 mm
(0.0004 ~ 0.0017 in)----
Clutch release method Inner push, cam push ----
Shifter:
Shifter type Cam drum and guide bar ----
Guide bar bending limit ---- 0.05 mm
(0.002 in)
Kickstarter:
Type Ratchet type ----
Carburetor:
USAEUROPE,
CDN, AUS, NZ,
ZA
I. D. mark 5TJ1 00 5TJ2 10 ----
Main jet (M.J) #150 #160 ----
Main air jet (M.A.J)ø2.0
←
----
Jet needle - clip position (J.N) OBDUT-4 OBDUQ-4 ----
Cutaway (C.A) 1.5
←
----
Pilot jet (P.J) #45 #48 ----
Pilot air jet (P.A.J) #70 #80 ----
Pilot outlet (P.O)ø0.9
←
----
Pilot screw (example) (P.S) 1-3/4 1-1/2 ----
Bypass (B.P)ø1.0
←
----
Valve seat size (V.S)ø3.8
←
----
Starter jet (G.S) #65
←
----
Leak jet (Acc.P) #70 #50 ----
Float height (F.H) 8 mm (0.31 in)
←
----
Engine idle speed 1,700 ~
1,900 r/min
←
----
Intake vacuum 33.3 ~ 38.7 kPa
(250 ~ 290 mmHg,
9.84 ~ 11.42 inHg)
←
----
Hot starter lever free play 3 ~ 6 mm
(0.12 ~ 0.24 in)
←
---- Item Standard Limit

SPEC
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MAINTENANCE SPECIFICATIONS
NOTE:
- marked portion shall be checked for torque tightening after break-in or before each race.
NOTE:
*1: Tighten the cylinder head bolts to 30 Nm (3.0 m · kg, 22 ft · lb) in the proper tightening sequence,
remove and retighten the cylinder head bolts to 20 Nm (2.0 m · kg, 14 ft · lb) in the proper tightening
sequence, and then tighten the cylinder head bolts further to reach the specified angle 180˚ in the
proper tightening sequence.Oil check bolt M6 × 1.0 1 10 1.0 7.2
Oil hose clamp–2 2 0.2 1.4
Clutch cover M6 × 1.0 7 10 1.0 7.2
Crankcase cover (right) M6 × 1.0 10 10 1.0 7.2
Crankcase cover (left) M6 × 1.0 9 10 1.0 7.2
Idle gear cover (starter motor) M6 × 1.0 2 10 1.0 7.2
Crankcase M6 × 1.0 12 12 1.2 8.7
Clutch cable holder M6 × 1.0 1 10 1.0 7.2
Oil drain bolt (crankcase rear) M10 × 1.25 1 20 2.0 14
(crankcase left) M6 × 1.0 1 10 1.0 7.2
Oil drain bolt (frame) M8 × 1.25 1 23 2.3 17
Oil strainer (frame) M18 × 1.5 1 90 9.0 65
Crankcase bearing stopper M6 × 1.0 15 10 1.0 7.2
Drive axle oil seal stopper M6 × 1.0 2 10 1.0 7.2
Ratchet wheel guide M6 × 1.0 2 12 1.2 8.7
Stopper plate M6 × 1.0 2 12 1.2 8.7
Kickstarter M8 × 1.25 1 33 3.3 24
Screw (kickstarter) M6 × 1.0 1 7 0.7 5.1
Starter clutch M6 × 1.0 6 16 1.6 11
Primary drive gear M20 × 1.0 1 75 7.5 54
Clutch boss M20 × 1.0 1 75 7.5 54
Push lever M6 × 1.0 1 10 1.0 7.2
Clutch spring M6 × 1.0 6 8 0.8 5.8
Balancer driven gear M14 × 1.0 1 50 5.0 36
Balancer weight plate M6 × 1.0 3 10 1.0 7.2
Drive sprocket M20 × 1.0 1 75 7.5 54
Drive sprocket cover M6 × 1.0 2 8 0.8 5.8
Shift pedal M6 × 1.0 1 12 1.2 8.7
Shift guide M6 × 1.0 2 10 1.0 7.2
Stopper lever M6 × 1.0 1 10 1.0 7.2
Segment M8 × 1.25 1 30 3.0 22 Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb