2010 YAMAHA WR 450F Ignition coil

1-9
SPECIAL TOOLS
Damper rod holder
YM-01494, 90890-01494Use this tool to remove and install
the damper rod.
Fork seal driver
YM-A0948, 90890-01502 This tool is used when install the fork
oil seal.
Spoke nipple wrench
YM-01521, 90980-01521 This tool is used to tighten the
spoke.
Sheave holder
YS-1880-A, 90890-01701 This tool is used for when loosening
or tightening the flywheel magneto
securing nut.
Pocket tester
YU-3112-C, 90890-03112 Use this tool to inspect the coil resis-
tance, output voltage and amper-
age.
Timing light
YM-33277-A, 90890-03141 This tool is necessary for checking
ignition timing.
Tool name/Part number How to use Illustration

2-3
MAINTENANCE SPECIFICATIONS
MAINTENANCE SPECIFICATIONS
ENGINEShock absorber:
Front shock absorber Coil spring/oil damper
Rear shock absorber Coil spring/gas, oil damper
Wheel travel:
Front wheel travel 300 mm (11.8 in)
Rear wheel travel 305 mm (12.0 in)
Electrical:
Ignition system CDI
Generator system AC magneto
Battery type YTZ7S (F)
Battery voltage/capacity 12V/6 AH
Specific gravity 1.310
Headlight type: Quartz bulb (halogen)
Bulb wattage × quantity:
Headlight 12 V 35/36.5 W × 1
Taillight 12 V 1.6/0.3 W × 1
Item Standard Limit
Cylinder head:
Warp limit ---- 0.05 mm (0.002
in)
Cylinder:
Bore size 95.00–95.01 mm (3.7402–3.7406 in) ----
Out of round limit ---- 0.05 mm (0.002
in)
Camshaft:
Drive method Chain drive (Left) ----
Camshaft cap inside diameter 22.000–22.021 mm (0.8661–0.8670 in) ----
Camshaft outside diameter 21.959–21.972 mm (0.8645–0.8650 in) ----
Shaft-to-cap clearance 0.028–0.062 mm (0.0011–0.0024 in) 0.08 mm (0.003
in)
Cam dimensions

2-10
MAINTENANCE SPECIFICATIONS
ELECTRICALDrive chain:
Type/manufacturer DID520VM/DAIDO ----
Number of links 113 links + joint ----
Chain slack 48–58 mm (1.9–2.3 in) ----
Chain length (15 links) ---- 239.3 mm
(9.42 in)
Front disc brake:
Disc outside dia. × Thickness 250 × 3.0 mm (9.84 × 0.12 in) 250 × 2.5 mm
(9.84 × 0.10 in)
Pad thickness 4.4 mm (0.17 in) 1.0 mm (0.04
in)
Master cylinder inside dia. 11.0 mm (0.433 in) ----
Caliper cylinder inside dia. 27.0 mm (1.063 in) × 2 ----
Brake fluid type DOT #4 ----
Rear disc brake:
Disc outside dia. × Thickness 245 × 4.0 mm (9.65 × 0.16 in) 245 × 3.5 mm
(9.65 × 0.14 in)
Deflection limit ---- 0.15 mm
(0.006 in)
Pad thickness 6.4 mm (0.25 in) 1.0 mm (0.04
in)
Master cylinder inside dia. 11.0 mm (0.433 in) ----
Caliper cylinder inside dia. 25.4 mm (1.000 in) × 1 ----
Brake fluid type DOT #4 ----
Brake lever and brake pedal:
Brake lever position 95 mm (3.74 in) ----
Brake pedal height (vertical height above footrest
top)10 mm (0.39 in) ----
Clutch lever free play (lever end) 8–13 mm (0.31–0.51 in) ----
Throttle grip free play3–5 mm (0.12–0.20 in) ---- Item Standard Limit
Item Standard Limit
Ignition system:
Advancer type Electrical ----
CDI: USA, CDN EUROPE AUS, NZ, ZA
Pickup coil resistance (color) 248–372 Ωat
20 °C (68 °F)
(White–Red)←←----
CDI unit-model/manufacturer 5TJ-E0/YAMA-
HA5TJ-L0/YAMA-
HA5TJ-F0/YAMA-
HA----
Ignition coil:
Model/manufacturer 5TA-10/DENSO ----
Minimum spark gap 6 mm (0.24 in) ----
Primary coil resistance 0.08–0.10 Ωat 20 °C (68 °F) ----
Secondary coil resistance 4.6–6.8 kΩat 20 °C (68 °F) ----

2-23
CABLE ROUTING DIAGRAM
1. Throttle cable (pull)
2. Throttle cable (return)
3. Catch tank hose
4. Ignition coil
5. Clamp
6. Air induction hose (air cut-off
valve - rear of cylinder head)
7. Catch tank breather hoseA. Cross the pull and push throttle
cables.
B. Fasten the catch tank hose and
air induction hose (air cut-off
valve-rear of cylinder head) onto
the frame. Locate the clamp end
facing toward the lower side of
the frame and cut off the tie end.
C. Fasten the catch tank breather
hose and carburetor breather
hoses together.D. Pass the carburetor breather
hose (of the throttle cable cover)
through the hose holder.

3-7
PRE-OPERATION INSPECTION AND MAINTENANCE
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation or practice, make sure the machine is in good operating condition.
Before using this machine, check the following points.
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
CoolantCheck that coolant is filled up to the radiator cap. Check the cool-
ing system for leakage.P.3-11 – 12
FuelCheck that a fresh gasoline is filled in the fuel tank. Check the fuel
line for leakage.P.1-18
Engine oilCheck that the oil level is correct. Check the crankcase and oil
line for leakage.P.3-14 – 15
Gear shifter and clutchCheck that gears can be shifted correctly in order and that the
clutch operates smoothly.P.3-12
Throttle grip/HousingCheck that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary.P.3-12 – 13
Brakes Check the play of front brake and effect of front and rear brake. P.3-19 – 22
Drive chainCheck drive chain slack and alignment. Check that the drive chain
is lubricated properly.P.3-22 – 23
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-26
SteeringCheck that the handlebar can be turned smoothly and have no ex-
cessive play.P.3-26 – 27
Front forks and rear shock
absorberCheck that they operate smoothly and there is no oil leakage.
P.3-23 – 26
Cables (wires)Check that the clutch and throttle cables move smoothly. Check
that they are not caught when the handlebars are turned or when
the front forks travel up and down.—
Exhaust pipe Check that the exhaust pipe is tightly mounted and has no cracks. P.3-10 – 11
Rear wheel sprocket Check that the rear wheel sprocket tightening bolt is not loose. P.3-22
Lubrication Check for smooth operation. Lubricate if necessary. P.3-28
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-20
Lead connectorsCheck that the AC magneto, CDI unit, and ignition coil are con-
nected tightly.P.1-7
SettingsIs the machine set suitably for the condition of the course and
weather or by taking into account the results of test runs before
riding? Are inspection and maintenance completely done?P.4-1 – 10

3-16
ENGINE
Using a digital engine tachometer for
idle speed adjustment, detect the en-
gine idling speed by bringing the
sensing element "c" of the engine ta-
chometer close to the ignition coil "2".
ADJUSTING THE VALVE
CLEARANCE
• This section is intended for those
who have basic knowledge and skill
concerning the servicing of Yama-
ha motorcycles (e.g., Yamaha deal-
ers, service engineers, etc.) Those
who have little knowledge and skill
concerning servicing are requested
not to undertake inspection, adjust-
ment, disassembly, or reassembly
only by reference to this manual. It
may lead to servicing trouble and
mechanical damage.
• The valve clearance should be ad-
justed when the engine is cool to
the touch.
• The piston must be at Top Dead
Center (T.D.C.) on compression
stroke to check or adjust the valve
clearance.
1. Remove:
• Seat
• Fuel tank
Refer to "SEAT, FUEL TANK
AND SIDE COVERS" section.2. Remove:
• Air cut-off valve assembly
Refer to "AIR INDUCTION SYS-
TEM" section in the CHAPTER 5.
• Spark plug
• Engine upper bracket
• Cylinder head cover
Refer to "CAMSHAFTS" section
in the CHAPTER 5.
3. Remove:
• Timing mark accessing screw "1"
• Crankshaft end accessing screw
"2"
• O-ring
4. Check:
• Valve clearance
Out of specification→Adjust.
Checking steps:
a. Turn the crankshaft counterclock-
wise with a wrench.
b. Align the T.D.C. mark "a" on the
rotor with the align mark "b" on the
crankcase cover when piston is at
T.D.C. on compression stroke.
In order to be sure that the piston is at
Top Dead Center, the punch mark "c"
on the exhaust camshaft and the
punch mark "d" on the intake cam-
shaft must align with the cylinder
head surface, as shown in the illustra-
tion.
c. Measure the valve clearance "e"
using a feeler gauge "1".
Record the measured reading if the
clearance is incorrect.
5. Adjust:
• Valve clearance
Adjustment steps:
a. Remove the camshaft (intake and
exhaust).
Refer to "CAMSHAFTS" section
in the CHAPTER 5.
b. Remove the valve lifters "1" and
the pads "2".
• Place a rag in the timing chain
space to prevent pads from falling
into the crankcase.
• Identity each valve lifter and pad
position very carefully so that they
can be reinstalled in their original
place.
To increase idle speed→Turn the
throttle stop screw "1" in "a".
To decrease idle speed→Turn the
throttle stop screw "1" out "b".
Engine idling speed:
1,750–1,950 r/min
Valve clearance (cold):
Intake valve:
0.10–0.15 mm
(0.0039–0.0059 in)
Exhaust valve:
0.20–0.25 mm
(0.0079–0.0098 in)

3-29
ELECTRICAL
ELECTRICAL
CHECKING THE SPARK PLUG
1. Remove:
• Spark plug
2. Inspect:
• Electrode "1"
Wear/damage→Replace.
• Insulator color "2"
Normal condition is a medium to
light tan color.
Distinctly different color→Check
the engine condition.
When the engine runs for many hours
at low speeds, the spark plug insula-
tor will become sooty, even if the en-
gine and carburetor are in good
operating condition.
3. Measure:
• Plug gap "a"
Use a wire gauge or thickness
gauge.
Out of specification→Regap.
4. Clean the plug with a spark plug
cleaner if necessary.
5. Tighten:
• Spark plug
• Before installing a spark plug, clean
the gasket surface and plug sur-
face.
• Finger-tighten "a" the spark plug
before torquing to specification "b".
CHECKING THE IGNITION TIMING
1. Remove:
• Timing mark accessing screw "1"
2. Attach:
• Timing light
• Digital tachometer
To the ignition coil lead (orange
lead"1").
3. Adjust:
• Engine idling speed
Refer to "ADJUSTING THE EN-
GINE IDLING SPEED" section.
4. Check:
• Ignition timing
Visually check the stationary
pointer "a" is within the firing
range "b" on the rotor.
Incorrect firing range→Check ro-
tor and pickup assembly.
5. Install:
• Timing mark accessing screw
CHECKING AND CHARGING THE
BATTERY
Batteries generate explosive hy-
drogen gas and contain electrolyte
which is made of poisonous and
highly caustic sulfuric acid. There-
fore, always follow these preven-
tive measures:
• Wear protective eye gear when
handling or working near batter-
ies.• Charge batteries in a well-venti-
lated area.
• Keep batteries away from fire,
sparks or open flames (e.g.,
welding equipment, lighted ciga-
rettes).
• DO NOT SMOKE when charging
or handling batteries.
• KEEP BATTERIES AND ELEC-
TROLYTE OUT OF REACH OF
CHILDREN.
• Avoid bodily contact with elec-
trolyte as it can cause severe
burns or permanent eye injury.
FIRST AID IN CASE OF BODILY
CONTACT:
EXTERNAL
• Skin — Wash with water.
• Eyes — Flush with water for 15
minutes and get immediate med-
ical attention.
INTERNAL
• Drink large quantities of water or
milk followed with milk of magne-
sia, beaten egg or vegetable oil.
Get immediate medical attention.
Charging time, charging amperage
and charging voltage for an MF
battery are different from those of
conventional batteries. The MF
battery should be charged as ex-
plained in the charging method il-
lustrations. If the battery is
overcharged, the electrolyte level
will drop considerably. Therefore,
take special care when charging
the battery.
Since MF batteries are sealed, it is
not possible to check the charge state
of the battery by measuring the spe-
cific gravity of the electrolyte. There-
fore, the charge of the battery has to
be checked by measuring the voltage
at the battery terminals.
1. Remove:
• Seat
2. Disconnect:
• Battery leads
(from the battery terminals)
First, disconnect the negative bat-
tery lead "1", and then the positive
battery lead "2".
Spark plug gap:
0.7–0.8 mm (0.028–
0.031 in)
Spark plug:
13 Nm (1.3 m•kg, 9.4
ft•lb)
Timing light:
YM-33277-A/90890-
03141

5-54
ENGINE REMOVAL
Ignition coil
Disconnect the AC magneto lead.
Disconnect the starter motor lead.Refer to "ELECTRIC STARTING SYSTEM"
section in the CHAPTER 7.
Negative battery lead Disconnect at the engine side.
1 Engine guard 1
2 Neutral switch 1
3 Drive chain sprocket cover 1
4 Nut (drive sprocket) 1 Refer to removal section.
5 Lock washer 1 Refer to removal section.
6 Drive sprocket 1 Refer to removal section.
7Clip 1
8 Bolt (brake pedal) 1
9 Brake pedal 1
10 Upper engine bracket 2
11 Lower engine bracket 2
12 Engine mounting bolt 3
13 Pivot shaft 1 Refer to removal section.
14 Engine 1 Refer to removal section. Order Part name Q'ty Remarks