An engine for a motorcycle having dummy covers for covering at least part of cylinder heads from the sides and overhead covers for covering at least part of head covers coupled to the cylinder heads from above and the sides. This configuration is provided in order to enhance the functional beauty of the engine wand to eliminate the need to provide specially shaped parts for cylinder heads, or the need provide a special surface treatment for the cylinder heads. At least one spot of dummy covers is fastened to an engine main unit including a cylinder head and a head cover with bolts. A plurality of engaging protrusions provided in overhead covers formed in a shape to cover the bolts are resiliently engaged with the engine main unit or the dummy covers so that the overhead covers are detachable or attachable.