Abstract: An improved body frame with a liquid tank secured integrally thereto for a motorcycle is disclosed which is constructed such that at least a part of the body frame is constituted of a pipe member. The improvement consists in that the liquid tank serving as an oil tank or the like is constituted by a combination of a main pipe fixedly connected to a head pipe and a gusset fixedly secured to said main pipe. The liquid tank includes a first holding chamber and a second holding chamber which are in communication with one another, said first holding chamber being defined by a combination of a part of the main pipe and the gusset, while said second holding chamber being defined by the inside space of the main pipe. Further, the liquid tank includes a defining chamber having a small holding capacity which is communication therewith, said defining chamber being equipped therein with a surface level detecting unit by means of which the surface level of liquid in the liquid tank is detected.