PURPOSE: To facilitate to connect a radiator to the pipes of outer units, as well as to enhance the radiating effect of a radiator, by combining a radiator with an oil cooler in one body.

CONSTITUTION: The discharge ports 27L, 27R, 27L' and 27R' of cooling water from an engine 18 are connected all together to one pipeline 27 on the outside of an engine 18, and the pipeline 27 is connected to a tank on the inlet side of cooling water for a radiator 40. A radiator 30 is positioned between a front fork and the left and the right side frames 20L and 20R, and fittings 33L and 33R, respectively set on the upper end of each side frame, and fixed to the upper surface of the side frames 20L and 20R. A large radiating area is provided to the radiator 30 which is formed in the shape of a gate so that it does not interfere with a cylinder head 18b which protrudes between the side frames 20L and 20R. On the right side of a radiator 30, an oil cooler 50 to cool lubricating oil is positioned being combined with the radiator 40 in one body, and is connected to the discharge port of an oil pump (not shown), passing through a pipeline 35 and the side frame 20R on the right side, which is connected to the pipeline 35.