2005 YAMAHA YFZ450 fuel

8-75
EBU13970
Idle speed adjustment
A special tester is needed to check the engine
r/min on this model.
Therefore, take the ATV to a Yamaha dealer to
have the idle speed adjusted.
EBU03030
Valve clearance adjustment
The correct valve clearance changes with use, re-
sulting in improper fuel/air supply or engine noise.
To prevent this, the valve clearance must be ad-
justed regularly. This adjustment however, should
be left to a professional Yamaha service techni-
cian. Specified idle speed:
1,750–1,850 r/min
U5TG61.book Page 75 Friday, April 2, 2004 11:28 AM

8-93 1. Locknut 2. Adjusting bolt
A. Cable length
1. Contre-écrou 2. Boulon de réglage
A. Longueur de câble
1. Contratuerca 2. Perno de ajuste
A. Longitud del cable
1. Locknut 2. Adjusting nut
1. Contre-écrou 2.Écrou de réglage
1. Contratuerca 2. Tuerca de ajuste
EBU14160
Parking brake adjustment
Parking brake adjustment may be required if the
parking brake does not hold properly. The cable
length
A should be adjusted to 56–60 mm.
1. Loosen the locknut and the adjusting nut on
the brake cable below the fuel tank.
2. Fully loosen the locknut and the adjusting bolt
at the rear brake caliper.
3. Turn the adjusting nut on the brake cable in
direction
a to increase the cable length or in
direction
b to decrease the cable length.NOTE:_ If the cable cannot be adjusted to specification,
consult a Yamaha dealer. _4. Tighten the locknut on the brake cable.
U5TG61.book Page 93 Friday, April 2, 2004 11:28 AM

8-143
EBU04130
Troubleshooting
Although Yamaha machines receive a rigid in-
spection before shipment from the factory, trouble
may occur during operation.
Any problem in the fuel, compression, or ignition
systems can cause poor starting and loss of pow-
er. The troubleshooting chart describes a quick,
easy procedure for making checks. If your ma-
chine requires any repair, take it to a Yamaha
dealer.
The skilled technicians at a Yamaha dealership
have the tools, experience, and know-how to prop-
erly service your machine. Use only genuine
Yamaha parts on your machine. Imitation parts
may look like Yamaha parts, but they are often in-
ferior. Consequently, they have a shorter service
life and can lead to expensive repair bills.
U5TG61.book Page 143 Friday, April 2, 2004 11:28 AM

8-145
WARNING
_ Do not smoke when checking the fuel system.
Fuel can ignite or explode, causing severe in-
jury or property damage. Make sure there are
no open flames or sparks in the area, including
pilot lights from water heaters or furnaces. _
U5TG61.book Page 145 Friday, April 2, 2004 11:28 AM

8-147
EBU07240Troubleshooting chart
Starting problems or poor engine performance1. Fuel
Check if there is fuel
in the fuel tank.There is fuel.Turn the fuel cock
lever to “OFF”.No fuel.Fuel cock is
clogged.
Clean the
fuel cock. Some fuel.Turn the fuel cock
lever to “RES”.Restart the engine.
No fuel.Supply fuel.
2. Compression
Use the electric
starter to see if
there is compression.There is compression.
Compression normal.
No compression.Ask a Yamaha dealer to
inspect.
3. Ignition
Remove the
spark plug and
check the electrodes.WetWipe clean with dry cloth.
DryAttach spark plug cap and
ground to chassis.Use the
electric starter.Spark is good.Ignition system is
normal.
Spark is weak.
Adjust the spark plug gap
or replace the spark plug. No spark.
Ask a Yamaha dealer to
inspect. 4. Battery
Use the electric starter.Engine turns over
quickly.Battery is good.
Engine turns over
slowly.Check the battery lead connections,
and charge the battery if necessary.Check the
fuel flow.
Turn the fuel cock
lever to “ON”.
Remove the fuel hose
from the fuel cock.
U5TG61.book Page 147 Friday, April 2, 2004 11:28 AM

9-7
EBU05260
B. STORAGE
Long term storage (60 days or more) of your ma-
chine will require some preventive procedures to
guard against deterioration. After thoroughly
cleaning the machine, prepare for storage as fol-
lows:
1. Fill the fuel tank with fresh fuel and add fuel
stabilizer (if available).NOTE:_ Use of fuel stabilizer eliminates the need to drain
the fuel system. Consult a Yamaha dealer if the
fuel system is to be drained instead. _2. Remove the spark plug, pour about one ta-
blespoon of SAE 10W30 or 20W40 motor oil
in the spark plug hole and reinstall the spark
plug. Ground the spark plug wire and turn the
engine over several times to coat the cylinder
wall with oil.
3. Clean the drive chain thoroughly and lubri-
cate it. (See page 8-107.)
4. Lubricate all control cables.
U5TG61.book Page 7 Friday, April 2, 2004 11:28 AM

10-1
EBU04280
1-SPECIFICATIONS
MODEL YFZ450
Dimension:
Overall length
Overall width
Overall height
Seat height
Wheel base
Ground clearance
Minimum turning radius1,840 mm
1,170 mm
1,090 mm
800 mm
1,280 mm
255 mm
3,500 mm
Basic weight:
With oil and full fuel tank 169.0 kg
Engine:
Type
Cylinder arrangement
Displacement
Bore
× stroke
Compression ratio
Starting system
Lubrication systemLiquid-cooled, 4-stroke, DOHC
Forward inclined single cylinder
439.0 cm
3
95.0
× 62.0 mm
11.90 : 1
Electric starter
Dry sump
U5TG61.book Page 1 Friday, April 2, 2004 11:28 AM

10-3
Radiator capacity (including all routes): 1.30 L
Air filter: Wet element
Fuel:
Type
Tank capacity
Reserve amountPREMIUM UNLEADED GASOLINE ONLY
For Europe:
PREMIUM UNLEADED GASOLINE ONLY with
a research octane number of 97 or higher
10.0 L
1.9 L
Carburetor:
Type
× quantity
ManufacturerFCR39H
× 1
KEIHIN
Spark plug:
Type/manufacturer
GapCR8E/NGK
0.7–0.8 mm
Clutch:
Type
OperationWet, multiple-disc
Left hand operation
Transmission:
Primary Reduction System
Primary Reduction Ratio
Secondary Reduction System
Secondary Reduction Ratio
Transmission type
OperationSpur gear
62/22 (2.818)
Chain drive
38/14 (2.714)
Constant mesh, 5-speed forward
Left foot operation MODEL YFZ450
U5TG61.book Page 3 Friday, April 2, 2004 11:28 AM