| 摘要 |
PURPOSE:To make a carburetor arrangeable within the width of an engine body as well as to aim at improvements in suction capacity through an auxiliary suction passage, by installing a driving shaft for a rotary valve in position separately from a crankshaft. CONSTITUTION:A rotary disk 73 is installed in an almost central part of engine width in a direction toward a crankshaft 44 in a way of deflecting its axial center from the crankshaft and paralleling it with the crankshaft 44, while a carburetor 78 is set up as directed at the rearward aslant to the leftward of the rotary disk 73. With this constitution, the carburetor 78 can be housed within the width of both sides of an engine 31 and, what is more, connection between the carburetor 78 and an air cleaner 27 can be done with a simple system route. In addition, at the more upstream side than the rotary dis, an auxiliary suction passage 83 interconnecting a suction passage and a crank chamber through is installed, and a reed valve 84 checking a back flow of an air-fuel mixture is installed in the auxiliary suction passage. Even though the rotary disk is made small diametrally, suction capacity can be supplemented by the auxiliary suction passage 83. |
