Starting And Break-In; Fuel; Air Filter Maintenance; Starting A Cold Engine - Yamaha YZ450FX 2019 Owner's Service Manual

EAM20123

STARTING AND BREAK-IN

EAM30193

FUEL

Always use the recommended fuel as stated be-
low. Also, be sure to use new gasoline the day
of a race.
Recommended fuel
Premium unleaded gasoline
(Gasohol [E10] acceptable)
Fuel tank capacity
8.2 L (2.2 US gal, 1.8 Imp.gal)
Fuel reserve amount
2.0 L (0.53 US gal, 0.44 Imp.gal)
ECA24180
NOTICE
Use only unleaded gasoline. The use of lead-
ed gasoline will cause severe damage to the
engine internal parts such as valves, piston
rings, and exhaust system, etc.
TIP
Your Yamaha engine has been designed to use
premium unleaded gasoline with a pump octane
number [(R+M)/2] of 91 or higher, or a research
octane number of 95 or higher. If knocking (or
pinging) occurs, use a gasoline of a different
brand.
EWA19010
WARNING
• For refueling, be sure to stop the engine
and use enough care not to spill any fuel.
Also be sure to avoid refueling close to a
fire.
• Refuel after the engine, exhaust pipe, etc.
have cooled off.
Gasohol
There are two types of gasohol: gasohol con-
taining ethanol and that containing methanol.
Gasohol containing ethanol can be used if the
ethanol content does not exceed 10 %. Gasohol
containing methanol is not recommended by
Yamaha because it can cause damage to the
fuel system or vehicle performance problems.
EAM30195

AIR FILTER MAINTENANCE

According to "CLEANING THE AIR FILTER EL-
EMENT" section in the CHAPTER 3, apply the
Yamaha foam air filter oil or other quality foam
air filter oil to the element. (Excess oil in the ele-
ment may adversely affect engine starting.)
STARTING AND BREAK-IN
EAM30196

STARTING A COLD ENGINE

1. Press the shift pedal to neutral.
2. Push the starter knob "1" completely.
TIP
• When the ambient temperature is 15 C (59 F)
or below, use the starter knob.
• Do not operate the throttle grip when operating
the starter knob.
3. Start the engine by pushing the start switch.
If the engine fails to start when using the start
switch, release it, wait a few seconds, and
then try again.
Each starting attempt should be as short as
possible to preserve the battery. Do not crank
the engine more than 10 seconds on any one
attempt.
4. When the engine starts running, warm this up
one or two minutes at a steady speed (of
3000 to 5000 r/min), and then return the start-
er knob to its original position.
TIP
When operating the throttle grip in the closing di-
rection, the starter knob "1" moves in the direc-
tion as shown and returns to its original position.
EWA19030
WARNING
Since exhaust gas contains harmful ingredi-
ents, do not start or warm it up at an illventi-
lated place or a closed narrow place.
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