Yamaha BIG BEAR PROFESSIONAL 400 YFM400FPT Owner's Manual page 194

Modifications
WARNING
_
Never modify this ATV through improper in-
stallation or use of accessories. All parts and
accessories added to this vehicle should be
genuine Yamaha or equivalent components
designed for use on this ATV and should be in-
stalled and used according to instructions.
Improper installation of accessories or modifi-
cation of this vehicle may cause changes in
handling which in some situations could lead
to an accident. If you have questions, consult
an authorized ATV dealer.
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