Yamaha YFM90RA Owner's Manual page 64

It is important when climbing a hill to make sure
that your weight is transferred forward on the ATV.
This can be accomplished by leaning forward and,
on steeper inclines, standing on the footboards
and leaning forward over the handlebars. Whenever
possible, ride straight up hills.
Slow down when you reach the crest of the hill if
you cannot see clearly what is on the other side –
there could be another person, an obstacle, or a
sharp drop-off. Use common sense and remember
that some hills are too steep for you to climb or
descend.
7
If you are climbing a hill and you find that you have
not properly judged your ability to make it to the
top, you should turn the ATV around while you still
have forward motion (provided you have the room
to do so) and go down the hill.
7-18
OK