(EN) An engine for a scooter, where valve lifters (33) are individually interposed between suction and exhaust valves (16, 17) and cam shafts (31, 32), and an axis line (C) of a cylinder (7) is extended toward the front of the vehicle. A stopper (42) opposed to a top face (33a) of each valve lifter (33) is provided on the cylinder (7). When the valve lifter (33) is moved, with a cam shaft removed from a cylinder head (12), to the direction where the valve lifter (33) comes out of the cylinder head (12), the top face (33a) of the valve lifter (33) is in contact with the stopper (42) so that the valve lifter (33) is prevented from falling out of the cylinder (7) by the stopper (42). Accordingly, even if the cam shaft is removed during maintenance, the valve lifter (33) is kept assembled in the cylinder (7). That is, a DOHC-type engine (2) can be mounted on a scooter with the valve lifter (33) being prevented from falling out of position during maintenance.
