Power transmission unit for in particular small-sized vehicles

摘要

The present invention relates to a power unit for, in particular small-sized, vehicles comprising an engine (105), a belt-type continuously variable transmission (110) accommodated in a transmission casing (101) extending rearward from a crankcase (104) of the engine (105), and a groove-width adjustment mechanism (7) for controlling a gear ratio of the transmission, wherein a hole (508) to permit a cylinder block to extend therethrough and a hole (600), through which the groove-width adjustment mechanism (7) extends, are formed on the crank case (104) so that center lines (D1,D2) thereof extend in parallel.