fuel YAMAHA YFZ450R 2012 User Guide

6-1
6
EBU19881
OPERATION
EBU19901Read the Owner’s Manual carefully before riding
the ATV. If there is a control or function you do not
understand, ask your Yamaha dealer.
WARNING
EWB00631Read the Owner ’s Manual carefully to become
familiar with all controls in order to help pre-
vent any loss of control, which could cause an
accident or injury.EBU29952Starting the engine NOTICEECB00150See the “Engine break-in ” section on page 6-4
prior to operating the engine for the first time.1. Set the parking brake.
2. Turn the key to “” (on) and the engine stop
switch to “”.
The following warning lights should come on
for a few seconds, then go off.

Coolant temperature warning light
Fuel level warning light
Engine trouble warning light
NOTICEECB00824If a warning light does not go off, see page 4-2
for the corresponding warning light circuit
check. To avoid possible damage, do not oper-
ate the ATV if a warning light stays on.3. Shift the transmission into neutral. The neutral indicator light should come on, if it does not
come on, have a Yamaha dealer check the
electrical circuit.TIPThis model is equipped with an ignition circuit cut-
off system. The engine can be started under the
following conditions.
The transmission is in neutral.
The clutch is disengaged with the transmission
in gear. However, it is recommended to shift into
neutral before starting the engine.
U18P66E0.book Page 1 Monday, May 16, 2011 4:23 PM

8-3
8
EBU21743Periodic maintenance chart for the emission control system TIP
For ATVs not equipped with an odometer or an hour meter, follow the month maintenance intervals.
For ATVs equipped with an odometer or an hour meter, follow the km (mi) or hours maintenance inter-
vals. However, keep in mind that if the ATV isn’t used for a long period of time, the month maintenance
intervals should be followed.
Items marked with an asterisk should be performed by a Yamaha dealer as they require special tools,
data and technical skills.NO. ITEM CHECK OR MAINTENANCE
JOB INITIAL
EVERY
Whichev- er comes first month136612
km
(mi) 320
(200) 1300
(800) 2500
(1600) 2500
(1600) 5000
(3200)
hours 20 80 160 160 320
1 *Fuel line 
Check fuel hoses for cracks or other damage, and
replace if necessary. √√√
 Replace. Every 5 years
2 *Spark plug 
Check condition and clean, regap, or replace if
necessary. √√√√√
3 *Valves Check valve clearance and adjust if necessary. √ √√√
4 *Crankcase breather
system 
Check breather hose for cracks or other damage,
and replace if necessary. √√√
U18P66E0.book Page 3 Monday, May 16, 2011 4:23 PM

8-8
8
EBU29430TIP
Some maintenance items need more frequent service if you are riding in unusually wet, dusty, sandy or
muddy areas, or at full-throttle.
Replace the fuel hose every five years and if cracked or damaged.
Hydraulic brake service
Regularly check and, if necessary, correct the brake fluid level.
 Every two years replace the internal components of the brake master cylinders and calipers, and
change the brake fluid.
 Replace the brake hoses every four years and if cracked or damaged.23 *Throttle lever 
Check operation.
 Check throttle lever free play, and adjust if neces-
sary.
 Lubricate cable and lever housing. √√√√√
24 *Front and rear brake
switches

Check operation and correct if necessary. √√√√√
25 *Lights and switches 
Check operation and correct if necessary.
 Adjust headlight beams. √√√√√
NO. ITEM
CHECK OR MAINTENANCE
JOB INITIAL EVERY
Whichev- er comes first month136612
km
(mi) 320
(200) 1300
(800) 2500
(1600) 2500
(1600) 5000
(3200)
hours 20 80 160 160 320U18P66E0.book Page 8 Monday, May 16, 2011 4:23 PM

8-9
8
EBU30130Removing and installing the cowling
and panels The cowling and panels shown need to be re-
moved to perform some of the maintenance jobs
described in this chapter. Refer to this section each
time a cowling or panel needs to be removed and
installed.
EBU29538Panel A (YFZ450RB)
To remove the panel1. Remove the seat. (See page 4-10.)
2. Remove the fuel tank cap by turning it coun-terclockwise. (See page 4-8.) NOTICE: Make
sure that no foreign material enters the
fuel tank.
[ECB01051]
3. Remove the bolts.
1. Panel A
2. Panel B
3. Cowling
1
2
3
1. Panel C
1
U18P66E0.book Page 9 Monday, May 16, 2011 4:23 PM

8-10
84. Remove the quick fasteners, and then slide
the panel backward and pull upward. 5. Install the fuel tank cap by turning it clockwise.
To install the panel
1. Remove the fuel tank cap by turning it coun- terclockwise.
2. Place the panel in the original position, and then install the quick fasteners. NOTICE:
When installing the panel, be sure not to
pinch the cables or wires.
[ECB00381]
3. Install the bolts.
4. Install the fuel tank cap by turning it clockwise.
5. Install the seat.
1. Bolt
1. Quick fastener
1 1
1
1. Projection
2. Slot
11
2
U18P66E0.book Page 10 Monday, May 16, 2011 4:23 PM

8-12
8To install the cowling
1. Place the cowling in the original position, and
then install the bolts.
2. Install panels C, B and A.EBU29595Panel A (YFZ450RSEB)
To remove the panel1. Remove the seat. (See page 4-10.)
2. Remove the fuel tank cap by turning it coun- terclockwise. (See page 4-8.) NOTICE: Make
sure that no foreign material enters the
fuel tank.
[ECB01051]
3. Loosen the quick fasteners.
1. Bolt
1. Bolt
11
1
1
U18P66E0.book Page 12 Monday, May 16, 2011 4:23 PM

8-13
8
4. Remove the quick fasteners, and then slide
the panel backward and pull upward. 5. Install the fuel tank cap by turning it clockwise.
To install the panel
1. Remove the fuel tank cap by turning it coun- terclockwise.
2. Place the panel in the original position, and then install the quick fasteners. NOTICE:
When installing the panel, be sure not to
pinch the cables or wires.
[ECB00381]
3. Tighten the quick fasteners.
4. Install the fuel tank cap by turning it clockwise.
5. Install the seat.
1. Quick fastener
1. Quick fastener
1 1
1
1. Projection
2. Slot
11
2
U18P66E0.book Page 13 Monday, May 16, 2011 4:23 PM

8-27
8
15. Insert the air filter element into the air filter
case, and then tighten the wing bolt. NOTICE:
Make sure that the air filter element is
properly seated in the air filter case. Never
operate the engine with the air filter ele-
ment removed. This will allow unfiltered air
to enter the engine, causing rapid engine
wear and possible engine damage. Addi-
tionally, operation without the air filter ele-
ment will affect the fuel injection system
with subsequent poor performance and
possible engine overheating.
[ECB00761]
16. Install the air filter case cover by hooking the holders onto the air filter case. 17. Install the seat.
TIPThe air filter element should be cleaned every 20
–
40 hours. It should be cleaned and lubricated more
often if the ATV is operated in extremely dusty ar-
eas. Each time the air filter element maintenance
is performed, check the air inlet of the air filter case
for obstructions. Check the air filter case rubber
joint to the throttle body and the rubber joint mani-
fold fittings for an air-tight seal. Tighten all fittings
securely to avoid the possibility of unfiltered air en-
tering the engine.EBU27703Cleaning the spark arrester Select a well-ventilated area free of combustible
materials and make sure the exhaust and muffler
are cool. 1. Remove the tailpipe bolt.
1. Washer
1
U18P66E0.book Page 27 Monday, May 16, 2011 4:23 PM

8-30
8The 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. 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.EBU29601Brakes Replacement of brake components requires pro-
fessional knowledge. Brake service should be per-
formed by a Yamaha dealer.
WARNING
EWB02571Operating with improperly serviced or adjust-
ed brakes could lead to a loss in braking ability
and an accident.EBU24130Checking the front and rear brake pads The front and rear brake pads must be checked for
wear at the intervals specified in the periodic main-
tenance and lubrication chart.
1. Rubber cover
2. Throttle lever free play adjusting bolt
3. Locknut
4. Throttle lever free play
32
4
(a)(b)
1U18P66E0.book Page 30 Monday, May 16, 2011 4:23 PM

8-52
8
EBU25740Troubleshooting Although Yamaha ATVs receive a thorough in-
spection before shipment from the factory, trouble
may occur during operation. Any problem in the fu-
el, compression, or ignition systems, for example,
can cause poor starting and loss of power.
The following troubleshooting charts represent
quick and easy procedures for checking these vital
systems yourself. However, should your ATV re-
quire any repair, take it to a Yamaha dealer, whose
skilled technicians have the necessary tools, expe-
rience, and know-how to service the ATV properly.
Use only genuine Yamaha replacement parts. Im-
itation parts may look like Yamaha parts, but they
are often inferior, have a shorter service life and
can lead to expensive repair bills.
WARNING
EWB02280Do not smoke when checking the fuel system.
Fuel can ignite or explode, causing severe inju-
ry or property damage. Make sure there are no
open flames or sparks in the area, including pi-
lot lights from water heaters or furnaces.U18P66E0.book Page 52 Monday, May 16, 2011 4:23 PM