Patent ID: 6691663
Filing Date: 2004-02-17
Classification: F02B,F02F

Abstract:
A cylinder head of a four-stroke internal combustion engine, comprising:a plurality of valve guides for respectively guiding and supporting an intake poppet valve and an exhaust poppet valve which slide in an opened or closed direction, the poppet valves having a substantially uniform thickness in the longitudinal direction of each valve guide, a depth in which at least one valve guide of the plurality of valve guides is fitted into one of a plurality of fitting holes of the cylinder head with a depth relative to depths by which the other valve guides are fitted into others of the fitting holes of the cylinder head, wherein: an idle fitting hole is formed above one of the fitting holes which is formed deeper in the cylinder head than the other fitting holes, the idle fitting hole extending upward to a lower side of a valve spring, the idle fitting hole having an inner diameter than inner larger than outer diameters of the valve guides inserted therein.