Yamaha YZ 2019 Series, Owner'S Service Manual

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STARTING AND BREAK-IN
1-20
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.
NOTICE
ECA24180
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.
WARNING
EWA19010
• 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.
EAM30194
HANDLING NOTE
WARNING
EWA19020
Never start or run the engine in a closed ar-
ea. The exhaust fumes are poisonous; they
can cause loss of consciousness and death
in a very short time. Always operate the ma-
chine in a well-ventilated area.
NOTICE
ECA25910
• If the throttle is open the air/ fuel mixture
may be too lean for the engine to start.
• Before starting the machine, perform the
checks in the pre-operation check list.
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.)
EAM30196
STARTING A COLD ENGINE
NOTICE
ECA24200
For maximum engine life, never accelerate
hard when the engine is cold!
In order for the ignition circuit cut-off system to
enable starting, one of the following conditions
must be met:
•
The transmission is in the neutral position.
• The transmission is in gear with the clutch lever
pulled.
1. Pull the starter knob/idle screw “1” to its full
length.
TIP
When the ambient temperature is 15

C (59

F)
or below, use the starter knob/idle screw.
2. Completely close the throttle.
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.
Recommended fuel
Premium unleaded gasoline
(Gasohol [E10] acceptable)
Fuel tank capacity
7.5 L (2.0 US gal, 1.7 Imp.gal)
Fuel reserve amount
2.1 L (0.55 US gal, 0.46 Imp.gal)
1