| US 7,484,492 B2 | ||
| Four-cycle internal combustion engine and vehicle | ||
| Takehiko Shiraoya, Shizuoka (Japan); Yasuyuki Hamanaka, Shizuoka (Japan); and Akira Takeda, Shizuoka (Japan) | ||
| Assigned to Yamaha Hatsudoki Kabushiki Kaisha, Shizuoka-Ken (Japan) | ||
| Filed on Jul. 03, 2007, as Appl. No. 11/773,238. | ||
| Claims priority of application No. 2006-187272 (JP), filed on Jul. 06, 2006. | ||
| Prior Publication US 2008/0006239 A1, Jan. 10, 2008 | ||
| Int. Cl. F02N 3/00 (2006.01); F01L 3/00 (2006.01) | ||
| U.S. Cl. 123—188.9 [123/188.12; 123/188.17] | 11 Claims |
| 1. A four-cycle internal combustion engine comprising:
a cylinder head having a port;
a valve having a fillet part and a stem part continuous with the fillet part for opening or closing the port;
a valve spring for urging the valve in a direction to close the port:
a valve guide for holding the stem part slidably;
a tubular spring guide for supporting an outer periphery part of the valve spring, wherein when the engine is disposed such
that the cylinder head is positioned on an upper side, a top end of the spring guide is positioned above a top end of the
valve guide; and
a spring retainer for retaining a top end of the valve spring, wherein the top end of the spring guide is positioned between
the top end of the valve guide and a bottom end of the spring retainer.
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