Power unit suspension system for motorcycles

In a motorcycle having a vehicle body frame and a power unit including an engine assembled integrally with a transmission and supporting an axle of a rear wheel, a suspension system for said power unit comprising:

• link means having an axis in its longitudinal direction extending substantially at right angles to the direction of principal vibratory forces of said engine;
• said link means being rotatable about a first pivot means while resiliently resisted, and about a second pivot means spaced apart in said longitudinal direction from said first pivot means;
• said first pivot means being secured to said frame and said second pivot means being secured to a first front lower portion of said power unit;
• whereby the entire rotational load acting on said power unit about said axle of said rear wheel is substantially converted into a moment of rotation of said link means;
• first elastic means provided for said link means to elastically support said power unit, said first elastic means being arranged between an upper portion of said link means and a second front lower portion of said power unit;
• said first elastic means being capable of producing a reaction force opposing said rotational load;
• and
• means for supporting a rear portion of said power unit from an upper portion of said frame, said supporting means including shock absorbing means.