COOLING METHOD FOR CYLINDER HEAD OF 4-CYCLE ENGINE

摘要

PURPOSE:To promote cooling of a part about an exhaust port and improve the durability of a tappet valve mechanism by guiding lubricating oil toward the exhaust valve spring seat of a cylinder head. CONSTITUTION:Lubricating oil which flows into a cam chamber 34 is guided to the exhaust valve spring seat 16 of the cylinder head 10 of an engine via a guiding means 50 which consists of a notch 40 and a rib 42. Lubricating oil which flows on the surface of the spring seat 16 and cools the portion drops into a cam chain chamber and is then returned to an oil pan. Cooling of a part of a cylinder block that is about the exhaust the exhaust port may be promoted and the durability of a tappet valve mechanism can be improved.