Yamaha BIG BEAR PROFESSIONAL 400 Manual Del Propietário página 224

If your ATV has stalled or stopped and you believe
you can continue up the hill, restart carefully to
make sure you do not lift the front wheels which
could cause you to lose control. If you are unable
to continue up the hill, dismount the ATV on the
uphill side. Physically turn the ATV around and
then descend the hill.
If you start to roll backwards, DO NOT use the rear
brake to stop or try to put the ATV in gear. The
ATV could easily tip over backwards. Instead, dis-
mount the ATV immediately on the uphill side.
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