Patent ID: 6959687

Claim:
An SOHC-type engine comprising first and second insertion/removal guide sections ( 68 , 69 ) for guiding the insertion and removal of first and second spark plugs ( 66 , 67 ), respectively, provided on a cylinder head ( 22 ) including an intake valve ( 47 ) and a first spark plug ( 67 ) disposed therein and arranged along an axis of a camshaft ( 34 ), and an exhaust valve ( 48 ) and a second spark plug ( 67 ) disposed therein and arranged along the axis of said camshaft ( 34 ), wherein a single rocker shaft ( 55 ) is disposed above said camshaft ( 34 ); and an intake-side rocker arm ( 59 ) pivotally following an intake-side cam ( 57 ) provided on said camshaft ( 34 ) to drive the intake valve ( 47 ) and an exhaust-side rocker arm ( 60 ) pivotally following an exhaust-side cam ( 58 ) provided on said camshaft ( 34 ) to drive the exhaust valve ( 48 ) carried commonly on said rocker shaft ( 55 ), wherein said first insertion/removal guide section ( 68 ) and the intake valve ( 47 ) are disposed so as to be superposed one on another at least partially in a view of projection onto a plane perpendicular to the axis of said camshaft ( 34 ), and said second insertion/removal guide section ( 69 ) and the exhaust valve ( 48 ) are disposed so as to be superposed one on another at least partially in a view of projection onto said plane.