As long as the bends do not decrease the ID of the raceway and do not use a radius less than the manufacturer requires you will be OK I am not sure how you would do this without some sort of mandrel tho. This plastic pipe gets pretty droopy if you just route the exhaust from the truck through it
353.24 Bends - How Made. Bends shall be so made that
the conduit will not be damaged and the internal diameter
of the conduit will not be effectively reduced. Bends shall
be permitted to be made manually without auxiliary equipment,
and the radius of the curve to the centerline of such
bends shall not be less than shown in Table 354.24. For
conduits of metric designators 129 and 155 (trade sizes 5
and 6) the allowable radii of bends shall be in accordance
with specifications provided by the manufacturer
