| 摘要 |
PURPOSE:To moderate a decrease of output, compensate overall power down of an output characteristic through the side of a sleeve valve and ensure the output, by providing the sleeve valve in a lower intake passage, branching at a carburetor side from reed valves in an intake passage and communicated to a crank chamber. CONSTITUTION:One end of an intake pipe 2, provided with a reed valve 1 and branch intake passage 31 in the outside of the reed valve, is mounted to an intake passage 10. The branch intake passage 31 constitutes a lower intake passage 3 with a passage 32 in a cylinder part and a passage 33 in a crankcase part, and is communicated to a crank case, then a sleeve valve 4 is provided on the half way of said passage 3. The sleeve valve 4 is synchronously rotated with a crankshaft, and two openings 41, 42 are formed at 180 deg. spaced in the peripheral wall of said valve 4. The sleeve valve 4 is rotated at a half speed of the crankshaft to communicate upper and down streams in the lower intake passage 3 only in a rising stroke when a piston is moved from its bottom dead center to its top dead center. |
