Body frame for a motorcycle

A body frame for a motorcycle including a head pipe portion and a body frame portion extending downwardly and rearwardly in an inverted U-shape from said head pipe, said body frame portion including left and right frame members coupled to each other comprising:

• said head pipe portion being in contact with only one of said left and right frame members;
• a cross member formed in an integral relationship with said body frame portion;
• a plurality of stays provided on said body frame;
• and
• a dividing plane formed at a front portion of said body frame and bypassing said head pipe portion, the dividing plane being located between the left and right frame members;
• said left and right frames being coupled together to form a unitary member.

A seat frame for a motorcycle including a front end connected to and extending rearwardly from an intermediate upper portion of a main frame of a motorcycle comprising:

• a seat rail disposed on an upper portion of said seat frame;
• back stays disposed on said upper portion of said seat frame and positioned adjacent a rear portion thereof;
• a cross member secured to said seat rail;
• mounting bosses being provided on said seat rail for securing elements thereto;
• a mud guard being disposed on an underside of said seat frame for mounting adjacent to a rear wheel of said motorcycle;
• said seat rail, back stays, cross member, mounting bosses and mud guard forming a seat frame member, two substantially symmetrical seat frame members being coupled together to form a unitary member.

A body frame for a motorcycle including a head pipe portion for supporting a rotary shaft for a handlebar comprising:

• a main body frame element connected to said head pipe and extending rearwardly of a motorcycle body;
• a first engine supporting member connected to and extending downwardly from said main body frame element adjacent to said head pipe, wherein an engine is capable of being supported at least at a lower end portion of said first engine supporting member and at a portion of said main body frame element in the longitudinal direction;
• said first engine supporting member being affixed directly to said head pipe portion corresponding to a location where a load from a wheel is transmitted to said main body frame element and extending rearwardly in the direction of said main body frame and projecting downwardly therefrom at an acute angle relative to the longitudinal axis of said head pipe;
• said main body frame element having a hollow sectional area with an increased sectional area adjacent to said first engine supporting member affixed to said head pipe portion and a second engine supporting portion, said hollow sectional area of said main body frame element is decreased in sectional area relative to the increased dimension adjacent to said first engine supporting member affixed to said head pipe portion and said second engine supporting portion at intermediate portions of said main body frame element disposed between the first engine supporting member and the second engine supporting portion and said main body frame including inner and outer side walls each having a height which gradually varies from said head pipe to said second engine supporting portion for forming a reduced inner and outer side wall height between the first engine supporting member to said second engine supporting member.