STARTING AND BREAK-IN
1-32
EAS2GB2050
STARTING AND BREAK-IN
EAS2GB2051FUEL
Always use the recommended fuel as stated
below. Also, be sure to use new gasoline the
day of a race.
ECA
NOTICE
Use only unleaded gasoline. The use of
leaded 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 oc-
tane number [(R+M)/2] of 91 or higher, or a re-
search octane number of 95 or higher. If
knocking (or pinging) occurs, use a gasoline of
a different brand.
EWA
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 (For USA and Canada)
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.
EAS2GB2052HANDLING NOTEEWA
WARNING
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.
ECA
NOTICE
• Unlike a two-stroke engine, this engine
cannot be kick started when the throttle is
open because the kickstarter may kick
back. Also, 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.
EAS2GB2053AIR FILTER MAINTENANCE
According to “CLEANING THE AIR FILTER
ELEMENT” section in the CHAPTER 3, apply
the foam-air-filter oil or its equivalent to the ele-
ment. (Excess oil in the element may adversely
affect engine starting.)
EAS2GB2054STARTING A COLD ENGINEECA
NOTICE
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 le-
ver 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. If the engine does not start
with the starter motor, try using the kickstart-
er. Recommended fuel
Premium unleaded gasoline
Fuel tank capacity
7.5 L (1.98 US gal, 1.65 lmp.gal)
Fuel reserve amount
1.6 L (0.42 US gal, 0.35 lmp.gal)
1
ENGINE SPECIFICATIONS
2-2
EAS2GB2064
ENGINE SPECIFICATIONS
Engine
Engine type Liquid cooled 4-stroke, DOHC
Displacement 250 cm
3
Cylinder arrangement Single cylinder
Bore stroke 77.0 53.6 mm (3.0 2.1 in)
Compression ratio 13.5:1
Starting system Electric starter and kickstarter
Fuel
Recommended fuel Premium unleaded gasoline only
Fuel tank capacity 7.5 L (1.98 US gal, 1.65 Imp.gal)
Fuel reserve amount 1.6 L (0.42 US gal, 0.35 Imp.gal)
Engine oil
Lubrication system Wet sump
Recommended brand YAMALUBE
Type SAE 10W-30, SAE 10W-40, SAE 10W-50,
SAE 15W-40, SAE 20W-40 or SAE 20W-50
Recommended engine oil grade API service SG type or higher, JASO standard
MA
Engine oil quantity
Quantity (disassembled) 1.10 L (1.16 US qt, 0.97 Imp.qt)
Without oil filter element replacement 0.83 L (0.88 US qt, 0.73 Imp.qt)
With oil filter element replacement 0.85 L (0.90 US qt, 0.75 Imp.qt)
Oil filter
Oil filter type Paper
Bypass valve opening pressure 40.0–80.0 kPa (0.40–0.80 kgf/cm
2,
5.8–11.6 psi)
Oil pump
Oil pump type Trochoid
Inner-rotor-to-outer-rotor-tip clearance Less than 0.150 mm (0.0059 in)
Limit 0.20 mm (0.0079 in)
Outer-rotor-to-oil-pump-housing clearance 0.13–0.18 mm (0.0051–0.0071 in)
Limit 0.24 mm (0.0094 in)
Oil-pump-housing-to-inner-and-outer-rotor
clearance 0.06–0.11 mm (0.0024–0.0043 in)
Limit 0.17 mm (0.0067 in)
Cooling system
Radiator capacity (including all routes) 1.00 L (1.06 US qt, 0.88 Imp.qt)
Radiator capacity 0.56 L (0.60 US qt, 0.50 Imp.qt)
Radiator cap opening pressure 107.9–137.3 kPa (1.08–1.37 kg/cm
2,
15.6–19.9 psi)
Radiator core
Width 112.6 mm (4.43 in)
Height 235.0 mm (9.25 in)
Depth 28.0 mm (1.10 in)
Water pump
Water pump type Single suction centrifugal pump
Spark plug
Manufacturer/model NGK/LMAR8G
Spark plug gap 0.7–0.8 mm (0.028–0.031 in)
