2012 YAMAHA YFZ450 check engine

8-31
8
EBU24047Adjusting the throttle lever free play The throttle lever free play should be checked and,
if necessary, adjusted at the intervals specified in
the periodic maintenance and lubrication chart.
The throttle lever free play should measure 2.0–
4.0 mm (0.08 –0.16 in) as shown. Periodically
check the throttle lever free play and, if necessary,
adjust it as follows.TIPThe engine idling speed must be checked, and ad-
justed if necessary, before adjusting the throttle le-
ver free play.1. Slide the rubber cover back.
2. Loosen the locknut.
3. To increase the throttle lever free play, turn the throttle lever free play adjusting bolt in di-
rection (a). To decrease the throttle lever free
play, turn the adjusting bolt in direction (b). 4. Tighten the locknut.
5. Slide the rubber cover to its original position.
EBU24060Valve clearance The valve clearance changes with use, resulting in
improper air-fuel mixture and/or engine noise. To
prevent this from occurring, the valve clearance
must be adjusted by a Yamaha dealer at the inter-
vals specified in the periodic maintenance and lu-
brication chart.1. Rubber cover
2. Throttle lever free play adjusting bolt
3. Locknut
4. Throttle lever free play
4
2
1
3
(a)
(b)
U1PD60E0.book Page 31 Monday, June 13, 2011 2:57 PM

8-43
8
EBU24882Lubricating the drive chain The drive chain must be cleaned and lubricated at
the intervals specified in the periodic maintenance
and lubrication chart, otherwise it will quickly wear
out, especially when riding in dusty or wet areas.
Service the drive chain as follows.NOTICEECB00561The drive chain must be lubricated after wash-
ing the ATV or riding in the rain or wet areas.1. Clean the drive chain with kerosene and asmall soft brush. NOTICE: To prevent dam-
aging the O-rings, do not clean the drive
chain with steam cleaners, high-pressure
washers or inappropriate solvents.
[ECB00571]
2. Wipe the drive chain dry.
3. Thoroughly lubricate the drive chain with a special O-ring chain lubricant. NOTICE: Do
not use engine oil or any other lubricants
for the drive chain, as they may contain
substances that could damage the O-
rings.
[ECB00581]
EBU24902
Checking and lubricating the cables The operation and the condition of all control ca-
bles should be checked before each ride, and the
cables and cable ends should be lubricated if nec-1. O-rings
1
1
U1PD60E0.book Page 43 Monday, June 13, 2011 2:57 PM

8-44
8essary. If a cable is damaged or does not move
smoothly, have a Yamaha dealer check or replace
it.
WARNING
EWB02581
Inspect cables frequently and replace if dam-
aged. Corrosion can result when the cable
sheaths become damaged, and cables can
also become frayed or kinked, which could
restrict the operation of controls and lead to
an accident or injury.
Always make sure all control cables work
smoothly before you begin riding in cold
weather. If the control cables are frozen or do
not work smoothly, you could be unable to
control the ATV, which could lead to an acci-
dent or collision.
EBU24922Checking and lubricating the brake and
clutch levers The operation of the brake and clutch levers
should be checked before each ride, and the lever
pivots should be lubricated if necessary.
Brake lever
Recommended lubricant:
Yamaha Chain and Cable Lube or engine oilRecommended lubricants: Brake lever:Silicone grease
Clutch lever: Lithium-soap-based grease
U1PD60E0.book Page 44 Monday, June 13, 2011 2:57 PM

8-57
8
EBU25784Troubleshooting charts Starting problems or poor engine performance
Check the fuel level in
the fuel tank.1. Fuel
There is enough fuel.There is no fuel.
Check the compression.
Supply fuel.
The engine does not start.
Check the compression.
Operate the electric starter.2. Compression
There is compression.
There is no compression.
Check the ignition. Have a Yamaha dealer
check the ATV.
Remove the spark plug
and check the electrodes.3. Ignition
Wipe off with a dry cloth and correct the
spark plug gap, or replace the spark plug.
Have a Yamaha dealer check the ATV.
The engine does not start.
Have a Yamaha dealer
check the ATV.
The engine does not start.
Check the battery.
Operate the electric starter.4. Battery
The engine turns over
quickly.
The engine turns over
slowly.
The battery is good.Check the battery lead connections,
and have a Yamaha dealer charge
the battery if necessary.
DryWet
Open the throttle halfway and operate
the electric starter.
U1PD60E0.book Page 57 Monday, June 13, 2011 2:57 PM

8-58
8Engine overheating
WARNING
EWB02290Wait for the engine and radiator to cool before removing the radiator cap. You could be burned by
hot fluid and steam blown out under pressure. Always put a thick rag over the cap when opening.
Allow any remaining pressure to escape before completely removing the cap.TIPIf coolant is not available, tap water can be temporarily used instead, provided that it is changed to the rec-
ommended coolant as soon as possible.Wait until the
engine has cooled.
Check the coolant level in the
reservoir and radiator.
The coolant level
is OK.The coolant level is low.
Check the cooling system
for leakage.
Have a Yamaha dealer check
and repair the cooling system.Add coolant. (See TIP.)
Start the engine. If the engine overheats again, have a
Yamaha dealer check and repair the cooling system.
There is
leakage.
There is
no leakage.
U1PD60E0.book Page 58 Monday, June 13, 2011 2:57 PM

9-2
9
EBU25933Storage Short-term
Always store your ATV in a cool, dry place and, if
necessary, protect it against dust with a porous
cover. NOTICE: Storing the ATV in a poorly ven-
tilated room or covering it with a tarp while it is
still wet, will allow water and humidity to seep
in and cause rust. To prevent corrosion, avoid
damp cellars, stables (because of the presence
of ammonia) and areas where strong chemi-
cals are stored.
[ECB00721]
Long-term
Before storing your ATV for several months: 1. Follow all the instructions in the “ Cleaning”
section of this chapter.
2. Turn the fuel cock lever to “OFF ”.
3. Drain the carburetor float chamber by loosen- ing the drain bolt; this will prevent fuel deposits
from building up. Pour the drained fuel into the
fuel tank.
4. Fill up the fuel tank and add fuel stabilizer (if available) to prevent the fuel from deteriorat-
ing. 5. Perform the following steps to protect the cyl-
inder, piston rings, etc. from corrosion.a. Remove the spark plug cap and spark plug.
b. Pour a teaspoonful of engine oil into the spark plug bore.
c. Install the spark plug cap onto the spark plug, and then place the spark plug on the
cylinder head so that the electrodes are
grounded. (This will limit sparking during
the next step.)
d. Turn the engine over several times with the starter. (This will coat the cylinder wall with
oil.)
e. Remove the spark plug cap from the spark plug, and then install the spark plug and
the spark plug cap.
6. Lubricate all control cables and the pivoting points of all levers and pedals.
7. Check and, if necessary, correct the tire air pressure, and then block up the ATV so that
all of its wheels are off the ground. Alternative-
Specified amount:
7.5 ml of stabilizer to each liter of fuel (or 1
oz of stabilizer to each gallon of fuel)U1PD60E0.book Page 2 Monday, June 13, 2011 2:57 PM

INDEX
AAccessories and loading ................................................ 6-7
Air filter element, cleaning ............................................ 8-24BBattery .......................................................................... 8-48
Brake and clutch levers, checking and lubricating ....... 8-44
Brake fluid, changing ................................................... 8-36
Brake fluid level, checking ........................................... 8-33
Brake lever ..................................................................... 4-5
Brake lever free play, checking the front ...................... 8-36
Brake light switches ..................................................... 8-38
Brake pads, checking the front and rear ...................... 8-32
Brake pedal .................................................................... 4-6
Brake pedal, checking and lubricating ......................... 8-45
Brake pedal height, checking ....................................... 8-36
Brakes .......................................................................... 8-32
Brakes, front and rear .................................................... 5-4CCables, checking and lubricating ................................. 8-43
Carburetor, adjusting ................................................... 8-30
Chassis fasteners .......................................................... 5-7
Cleaning ......................................................................... 9-1
Clutch lever .................................................................... 4-5
Clutch lever free play, adjusting ................................... 8-39
Coolant .................................................................. 5-4, 8-20
Coolant temperature warning light ................................. 4-2DDrive chain ..................................................................... 5-5Drive chain, lubricating ................................................ 8-43
Drive chain slack .......................................................... 8-41
EEngine break-in .............................................................. 6-5
Engine, cold start ........................................................... 6-1
Engine idling speed ..................................................... 8-30
Engine oil ....................................................................... 5-4
Engine oil and oil filter element .................................... 8-14
Engine, starting a warm ................................................. 6-3
Engine stop switch ......................................................... 4-3FFuel ......................................................................... 4-8, 5-4
Fuel cock ..................................................................... 4-10
Fuel tank cap ................................................................. 4-8
Fuse, replacing ............................................................ 8-50HHandlebar switches ....................................................... 4-3
Headlight beam, adjusting ........................................... 8-53
Headlight bulb, replacing ............................................. 8-51IIdentification numbers .................................................. 11-1
Indicator light and warning light ..................................... 4-2
Instruments, lights and switches .................................... 5-7LLabel locations ............................................................... 1-1
Light switch .................................................................... 4-3MMain switch .................................................................... 4-1
U1PD60E0.book Page 1 Monday, June 13, 2011 2:57 PM