2016 YAMAHA YZ450F Owners Manual

BASIC SERVICE INFORMATION
1-11
Checking the connections
Check leads, couplers, and connectors for
stains, rust, moisture, etc.
1. Disconnect:
• Lead
• Coupler
• Connector
ECA16780
NOTICE
• When disconnecting a coupler, release the
coupler lock, hold both sections of the
coupler, and then disconnect the coupler.
• There are many types of coupler locks;
therefore, be sure to check the type of cou-
pler lock before disconnecting the cou-
pler.
ECA16790
NOTICE
When disconnecting a connector, do not
pull the leads. Hold both sections of the
connector, and then disconnect the con-
nector.2. Check:
• Lead
• Coupler
• Connector
Moisture  Dry with compressed air.
Rust/stains  Connect and disconnect sev-
eral times.
3. Check:
• All connections
Loose connection  Connect properly.
TIP
• If the pin “1” on the terminal is flattened, bend
it up.
• After disassembling or assembling a coupler,
pull on the leads to make sure that they are in-
stalled securely.
1

BASIC SERVICE INFORMATION
1-12
4. Connect:
• Lead
• Coupler
• Connector
TIP
• When connecting a coupler or a connector,
make sure that both terminals are connected
securely.
• Make sure all connections are tight.5. Check:
• No continuity
TIP
• If there is no continuity, clean the terminals.
• When checking the wire harness, perform
steps (1) to (4).
• As a quick remedy, use a contact revitalizer
available at most part stores.
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C

SPECIAL TOOLS
1-13
EASB111028
SPECIAL TOOLS
The following special tools are required for accurate and complete adjustment and assembly. Using
the correct special tool will help prevent damage caused by the use of improper tools or improvised
techniques. The shape and tool number used for the special tool differ by country, so two types are
provided. Refer to the list provided to avoid errors when placing an order.
TIP
• For U.S.A. and Canada, use tool number starting with “YM-”, “YU-”, or “ACC-”.
• For others, use tool number starting with “90890-”.
Tool name/Part number How to use Illustration
Dial gauge & stand set
90890-01252
Dial gauge set
YU-03097-BThis tool is used to check
parts for runout or bend.
Crankshaft installer pot
90890-01274
Installing pot
YU-90058This tool is used to install the
crankshaft.
Crankshaft installer bolt
90890-01275
Bolts
YU-90060This tool is used to install the
crankshaft.
Adapter (M12)
90890-01278
Adapter #3
YU-90063This tool is used to install the
crankshaft.
Piston pin puller set
90890-01304
Piston pin puller
YU-01304This tool is used to remove
the piston pin.

SPECIAL TOOLS
1-14
Radiator cap tester
90890-01325
Mityvac cooling system tester
kit
YU-24460-AThis tool is used to check the
radiator and the radiator cap.
Radiator cap tester adapter
90890-01352
Pressure tester adapter
YU-33984This tool is used to check the
radiator and the radiator cap.
Steering nut wrench
90890-01403
Exhaust flange nut wrench
YU-A9472This tool is used to remove or
tighten the steering nut.
Cap bolt wrench
90890-01500
YM-01500This tool is used to remove or
tighten the base valve.
Cap bolt ring wrench
90890-01501
YM-01501This tool is used to loosen or
tighten the damper assem-
bly.
Fork seal driver
90890-01502
YM-A0948This tool is used to install the
oil seal of the front fork.
Spoke nipple wrench (6–7)
90890-01521
YM-01521This tool is used to tighten the
spoke. Tool name/Part number How to use Illustration

SPECIAL TOOLS
1-15
Pocket tester
90890-03112
Analog pocket tester
YU-03112-CThis tool is used to measure
the voltage, current, and re-
sistance of electrical compo-
nents.
Timing light
90890-03141
YU-03141This tool is used to measure
the ignition timing.
Pressure gauge
90890-03153
YU-03153This tool is used to measure
the fuel pressure.
Fuel pressure adapter
90890-03186
YM-03186This tool is used to mount the
pressure gauge.
Test harness S-pressure
sensor (3P)
90890-03207
YU-03207This tool is used to check the
throttle position sensor input
voltage.
FI diagnostic tool sub-lead
90890-03212
YU-03212This tool is used to connect
the Yamaha diagnostic tool
to a battery.
Yamaha diagnostic tool
90890-03231
Yamaha diagnostic tool (US)
90890-03234This tool is used to check er-
ror codes or carry out self-di-
agnosis.
Valve guide remover & in-
staller set (ø5.5)
90890-04016This tool is used to replace
the valve guide.
Valve guide remover (5.5
mm)
YM-01122
Valve guide installer (5.5
mm)
YM-04015
Valve guide reamer (5.5 mm)
YM-01196Tool name/Part number How to use Illustration

SPECIAL TOOLS
1-16
Valve spring compressor
90890-04019
YM-04019This tool is used to discon-
nect or connect the valve and
the valve spring.
Spacer (crankshaft installer)
90890-04081
Pot spacer
YM-91044This tool is used to install the
crankshaft.
Clutch holder
90890-04086
YM-91042This tool is used to hold the
clutch when removing or in-
stalling the clutch boss secur-
ing nut.
Valve lapper
90890-04101
Valve lapping tool
YM-A8998This tool is used to remove
the valve lifter or lap the
valve.
Valve spring compressor
adapter 22 mm
90890-04108
YM-04108This tool is used to discon-
nect or connect the valve and
the valve spring.
Rotor puller
90890-04151
YM-04151This tool is used to remove
the rotor. Tool name/Part number How to use Illustration
YM-04019
YM-91044

SPECIAL TOOLS
1-17
Crankcase separating tool
90890-04152
YU-A9642This tool is used to remove
the crankshaft.
Ignition checker
90890-06754
Oppama pet-4000 spark
checker
YM-34487This tool is used to check the
spark performance of the ig-
nition coil.
Digital tachometer
90890-06760
YU-39951-BThis tool is used to measure
the engine speed.
Three bond No.1215®
90890-85505This sealant (Bond) is used
for crankcase mating sur-
face, etc. Tool name/Part number How to use Illustration

CONTROL FUNCTIONS
1-18
EASB111029
CONTROL FUNCTIONS
EASB111030ENGINE STOP SWITCH
The engine stop switch “1” is located on the left
handlebar. Continue pushing the engine stop
switch till the engine comes to a stop.
EASB111031LAUNCH CONTROL SWITCH
The launch control switch “1” is located on top
of the left handlebar.
When the launch control switch is pressed, the
ignition timing is delayed to reduce slipping at
the rear wheel which occurs when the vehicle
accelerates from a stationary position.
This can be used to starting off in a stable man-
ner on a slippery road surface.
However, the effect may not be adequate de-
pending on the rider’s operations and road sur-
face conditions.
How to operate
1. Put the gear into the neutral position.
2. Start the engine.
3. Push the launch control switch for more than
one second to turn on the launch control
switch.
TIP
When the launch control switch is turned on, in-
dicator “2” will flash.
4. Put the gear into the 1st or 2nd gear for start-
ing off.
5. After starting off, the launch control switch
will turn off automatically when the gear is
shifted into the 3rd gear.
The launch control switch will also turn off when
the engine is stopped or the gear is shifted into
the 3rd gear or higher.
TIP
When the launch control switch is turned off, in-
dicator will stop flashing.
EASB111032CLUTCH LEVER
The clutch lever “1” is located on the left han-
dlebar. The clutch lever disengages or engag-
es the clutch.
Pull the clutch lever toward the handlebar to
disengage the clutch, and release the lever to
engage the clutch.
EASB111033SHIFT PEDAL
The shift pedal “1” has adopted a method of 1
down & 4 ups (press-down & kick-ups).
Press it down for N (neutral) to 1st, and kick it
up for 2nd to 5th.
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