Page 25 of 168

2-3
2 steady speed when climbing a hill. If you stall or
roll backwards, follow the special procedure for
braking described in this manual. Dismount on
the uphill side or to a side if pointed straight up-
hill. Turn the ATV around and remount, following
the procedure described in this manual.
Always check for obstacles before operating in a
new area.Never attempt to operate over large obstacles,
such as large rocks or fallen trees. Always follow
proper procedures when operating over obsta-
cles as described in this manual.Always be careful when skidding or sliding.
Learn to safely control skidding or sliding by
practicing at low speeds and on level, smooth
terrain. On extremely slippery surfaces, such as
ice, go slowly and be very cautious in order to re-
duce the chance of skidding or sliding out of con-
trol.Never operate an ATV in fast flowing water or in
water deeper than that recommended in this
manual. Remember that wet brakes may have
reduced stopping ability. Test your brakes after
leaving water. If necessary, apply them several
times to let friction dry out the linings.
Always be sure there are no obstacles or people
behind you when you operate in reverse. When
it is safe to proceed in reverse, go slowly.Always use the size and type of tires specified in
this manual.Always maintain proper tire pressure as de-
scribed in this manual.Never modify an ATV through improper installa-
tion or use of accessories.Never exceed the stated load capacity for an
ATV. Cargo should be properly distributed and
securely attached. Reduce speed and follow in-
structions in this manual for carrying cargo or
pulling a trailer. Allow greater distance for brak-
ing.
WARNING
EWB00071Avoid Carbon Monoxide Poisoning
All engine exhaust contains carbon monoxide,
a deadly gas. Breathing carbon monoxide can
cause headaches, dizziness, drowsiness, nau-
sea, confusion, and eventually death.
Carbon Monoxide is a colorless, odorless,
tasteless gas which may be present even if you
do not see or smell any engine exhaust. Deadly
levels of carbon monoxide can collect rapidly
U28P61E0.book Page 3 Wednesday, March 18, 2009 9:25 AM
Page 58 of 168
5-6
5
Tire information
This ATV is equipped with tubeless tires with
valves.
WARNING
EWB02551Use of improper tires on this ATV may cause
loss of control, increasing your risk of an acci-
dent.After extensive tests, only the tires listed below
have been approved for this model by Yamaha
Motor Co., Ltd.1. Tire wear limit
Front:
Manufacturer/model:
YFM550FAPZ CHENG SHIN/C828-4P
YFM550FAZ CHENG SHIN/C828-4P
YFM5FGPHZ DUNLOP/KT421
YFM5FGPZ DUNLOP/KT421
YFM5FGZ DUNLOP/KT421
Size:
AT25 x 8-12
Ty p e :
Tu b e l e s s
Rear:
Manufacturer/model:
YFM550FAPZ CHENG SHIN/C828-4P
YFM550FAZ CHENG SHIN/C828-4P
YFM5FGPHZ DUNLOP/KT425
YFM5FGPZ DUNLOP/KT425
YFM5FGZ DUNLOP/KT425
Size:
AT25 x 10-12
Ty p e :
Tu b e l e s s
U28P61E0.book Page 6 Wednesday, March 18, 2009 9:25 AM
Page 59 of 168
5-7
5 Aftermarket tires and rims
The tires and rims that came with your ATV were
designed to match the performance capabilities
and to provide the best combination of handling,
braking, and comfort. Other tires, rims, sizes, and
combinations may not be appropriate.
EBU19840Chassis fasteners Make sure that all nuts, bolts and screws are prop-
erly tightened.EBU19850Instruments, lights and switches Check that all instruments, lights and switches are
working properly. Correct if necessary.U28P61E0.book Page 7 Wednesday, March 18, 2009 9:25 AM
Page 160 of 168

10-3
10
Spark plug gap:
0.8–0.9 mm (0.031–0.035 in)Clutch:Clutch type:
Wet, centrifugal automaticTransmission:Primary reduction system:
V-belt
Secondary reduction system:
Shaft drive
Secondary reduction ratio:
41/21 × 24/18 × 33/9 (9.544)
Transmission type:
V-belt automatic
Operation:
Left hand operation
Reverse gear:
23/14 × 28/23 (2.000)
Low range:
31/16 (1.938)
High range:
31/27 (1.148)Chassis:Frame type:
Steel tube frame
Caster angle:
5.0 °
Trail:
26.0 mm (1.02 in)
Front tire:Type:
Tubeless
Size:
AT25 x 8-12
Manufacturer/model:
YFM550FAPZ CHENG SHIN/C828-4P
YFM550FAZ CHENG SHIN/C828-4P
YFM5FGPHZ DUNLOP/KT421
YFM5FGPZ DUNLOP/KT421
YFM5FGZ DUNLOP/KT421Rear tire:Type:
Tubeless
Size:
AT25 x 10-12
Manufacturer/model:
YFM550FAPZ CHENG SHIN/C828-4P
YFM550FAZ CHENG SHIN/C828-4P
YFM5FGPHZ DUNLOP/KT425
YFM5FGPZ DUNLOP/KT425
YFM5FGZ DUNLOP/KT425Loading:Maximum loading limit:
220.0 kg (485 lb)
(Total weight of rider, cargo, accessories, and tongue)Tire air pressure (measured on cold tires):Recommended:
Front:
35.0 kPa (0.350 kgf/cm², 5.0 psi)
U28P61E0.book Page 3 Wednesday, March 18, 2009 9:25 AM