APRILIA SXV450 - 2007 Manual page 10

Using a hook spanner, turn the upper eccentric ring nut
by 180°.
WARNING
Accurately line up the notch on the ring nut with
the point where the tubes of the frame meet
(vehicle axis).
Restore the vehicle following, in reverse, the procedure
just described.
FORK OFFSET ADJUSTMENT
Loosen the headstock nut.
Loosen the screw that closes the upper plate.
Loosen the screw that closes the lower plate.