Section 1251. Riding on motorcycles

(a)  A person operating a motorcycle
  shall ride only upon the permanent and regular  seat  attached  thereto,
  and  such  operator shall not carry any other person nor shall any other
  person ride on a motorcycle unless such motorcycle is designed to  carry
  more  than  one  person,  in  which  event a passenger may ride upon the
  permanent and regular seat if designed for two persons, or upon  another
  seat  firmly  attached  to  the  motorcycle  at  the rear or side of the
  operator.
    (b) A person shall ride upon a motorcycle only while  sitting  astride
  the  seat,  facing forward, with one leg on each side of the motorcycle,
  unless said person is seated in a sidecar affixed to said motorcycle.
    (c) No person shall operate a motorcycle while carrying  any  package,
  bundle  or  other  article which prevents him from keeping both hands on
  the handlebars.
    (d) No operator shall carry any person, nor shall any person ride,  in
  a  position  that  will  interfere  with the operation or control of the
  motorcycle or the view of the operator.