2009 YAMAHA YFM90R ignition

4-2
4
Handlebar switches Engine stop switch “ENG. STOP”
Set this switch to “RUN” before starting the engine.
The engine stop switch controls the ignition and
stops the engine when it is running. Use this switch
to stop the engine in an emergency situation. The
engine will not start or run when this switch is set
to “OFF”.
Start switch “START”
Push this switch to crank the engine with the start-
er.
See the starting instructions on page 6-1 prior
to starting the engine.
1
2
1. Engine stop switch “ENG. STOP”
2. Start switch “START”

6-2
Ambient temp./choke position
5. Completely close the throttle lever and start
the engine by pushing the start switch.TIPIf the engine fails to start, release the start switch,
then push it again. Pause a few seconds before
the next attempt. Each cranking should be as short
as possible to preserve battery energy. Do not1. Fully open “ON”
2. Half open (warming up position)
3. Closed “OFF”
4. Choke
0°
30° 10°
20° 30°
50° 70° 90° °F
°C
1
3
TIPThis model is equipped with an ignition circuit cut-
off system. The engine can be started only when
the rear brake lever is applied.4. Use the choke in reference to the figure:
Position (1):Cold engine start with ambient temperature be-
low 30 °C (90 °F).
Position (2):Warming up position.
Position (3):Cold engine start with ambient temperature
above 25 °C (80 °F).
66
1 3
2 4

8-34
TroubleshootingAlthough 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 chart represents a
quick and easy procedure 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.
8
WARNING
Do 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.

8-35
Troubleshooting chart
Check the fuel level in
the fuel tank.1. Fuel
There is enough fuel.There is no fuel.
Check the compression.
Supply fuel.
The engine does not start.
Check the compression.
Operate the electric starter.2. Compression
There is compression.
There is no compression.
Check the ignition. Have a Yamaha dealer
check the ATV.
Remove the spark plug
and check the electrodes.3. Ignition
Wipe off with a dry cloth and correct the
spark plug gap, or replace the spark plug.
Have a Yamaha dealer check the ATV.
The engine does not start.
Have a Yamaha dealer
check the ATV.
The engine does not start.
Check the battery.
Operate the electric starter.4. Battery
The engine turns over
quickly.
The engine turns over
slowly.
The battery is good.Check the battery lead connections, and
charge the battery if necessary.
DryWet
Open the throttle halfway and operate
the electric starter.
8

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10
Electrical system:Ignition system: CDI
Charging system: AC magnetoBattery:Model:
GTX5L-BS
Voltage, capacity: 12 V,4 .0 Ah Fuses:Main fuse: 10 A Noise and vibration level:Noise level (77/311/EEC):
77.4 dB(A) (EUR)
Vibration on seat (EN1032, ISO5008): Will not exceed 0.5 m/s
2 (EUR)
Vibration on handlebar (EN1032, ISO5008): Will not exceed 2.5 m/s2 (EUR)
Rear suspension:Type:Swingarm
Spring/shock absorber type: Coil spring/oil damper
Wheel travel: 83 mm (3.3 in)