Throttle valve opening control device and layout structure thereof

A throttle valve opening control device (140) includes a drum which is connected to a throttle grip by a wire, an input shaft which is integrally mounted in the drum, an output shaft (151) which is connected to the input shaft by way of a power transmission device, a link mechanism (138) which connects the output shaft (151) to a front valve shaft (81) and a rear valve shaft (101), and a drive motor (188) which drives the power transmission device to provide the relative rotation of the output shaft (151) with respect to the input shaft, wherein the input shaft and the output shaft (151) have respective axes thereof arranged on a straight line, the drive motor (188) is arranged parallel to the output shaft (151), and the output shaft (151) and the drive motor (188) are juxtaposed vertically substantially along a center line (165) of an intake passage. It is possible to make the throttle valve opening control device compact and, at the same time, it is possible to make the throttle valve opening control device closer to a throttle body whereby the engine on which the throttle valve opening control device is mounted can be miniaturized.