Straddled vehicle starter motor, engine start-up device, and straddled vehicle

A straddled vehicle starter motor for starting up an engine mounted to a straddled vehicle, the straddled vehicle starter motor comprising:

• a rotor configured to be rotatable, and including
• a winding,
• a core with the winding wound thereon, and
• a commutator electrically connected to the winding;
• a brush configured to contact the commutator to cause a current to be supplied to the rotor, a position of the brush being fixed with respect to a rotation direction of the rotor;
• and
• a movable permanent magnet arranged to oppose the core with a gap therebetween and to be movable in a circumferential direction of the rotor, independently of the rotor, within an angle range, the angle range including
• a retarded angle position in which the movable permanent magnet is displaced in a retarded angle direction relative to the brush, to thereby cause a first torque, and
• an advanced angle position in which the movable permanent magnet is displaced in an advanced angle direction relative to the brush,
• to thereby cause a second torque that is higher than the first torque, the movable permanent magnet being configured to be located in the advanced angle position at a time point when the rotor starts to rotate upon a supply of the current to the rotor, and to be moved in the retarded angle direction to the retarded angle position within a first period in which the rotor is rotating with the current supplied to the rotor.