The Collaborative International Dictionary of English v.0.48:

Motor \Mo"tor\, Motory \Mo"to*ry\, Motorial \Mo*to"ri*al\, a.
   [L. motorius that has motion. See Motor, n.]
   Causing or setting up motion; pertaining to organs of motion;
   -- applied especially in physiology to those nerves or nerve
   fibers which only convey impressions from a nerve center to
   muscles, thereby causing motion.
   [1913 Webster]

WordNet (r) 3.0 (2006):

motorial
    adj 1: of nerves and nerve impulses; conveying information away
           from the CNS; "efferent nerves and impulses" [syn:
           efferent, motorial] [ant: afferent]