Straddle type vehicle with a single cylinder engine fixed to a vehicle frame, a seat for a rider supported at the vehicle frame, a pair of footrests (3a,3b) for the rider attached to the vehicle frame, and at least one front wheel, said single cylinder engine comprises: a crankcase accommodating a crank mechanism, a cylinder block having a single cylinder bore accommodating a piston connected with the crank mechanism, a cylinder head arranged at a top end of the cylinder block, and a bottom end of the cylinder block is arranged at an upper part of the crank case, said cylinder block and/or said cylinder head are at least partially exposed to the outside of the vehicle, wherein the crank case comprises a first side cover lid attached to the crank case to constitute an outermost portion of the crank case in width direction of the vehicle, said first side cover lid is exposed to the outside, wherein a cover means comprises at least a first cover portion arranged under said first side cover lid, said first cover portion comprises a side section (9a1) that extends in a downward direction to cover a space under the crank case and intersects an imaginary plan that contains a road contact point of the front wheel and outermost portions of the footrests (3a,3b) in width direction of the vehicle, and the crank case comprises a second side cover lid attached to the crank case to constitute an outermost portion of the crank case in width direction of the vehicle, said second side cover lid is exposed to the outside, and the cover means comprises at least a second cover portion arranged under said second side cover lid, said second cover portion comprises a side section (9b1) that extends in a downward direction to cover the space under the crank case and intersects the imaginary plan that contains the road contact point of the front wheel and outermost portions of the footrests (3a,3b) in width direction of the vehicle, wherein the first side cover lid and the second side cover lid are exposed to opposing outside of the vehicle and constitutes outermost portions of the crank case in width direction of the vehicle, and the cover means comprises a third cover portion arranged in width direction of the vehicle and connecting the first and second cover portions (9a, 9b), said third cover portion intersects the imaginary plan that contains the road contact point of the front wheel and outermost portions of the footrests (3a,3b) in width direction of the vehicle, front end sections (9a2, 9b2) of the first and second cover portions (9a, 9b) are extending further forward of the vehicle than a central section (9c1) of said third cover portion, characterised in that the three cover means (9a, 9b, 9c) are provided as separate elements, which in combination form the cover means. a crankcase accommodating a crank mechanism, a cylinder block having a single cylinder bore accommodating a piston connected with the crank mechanism, a cylinder head arranged at a top end of the cylinder block, and a bottom end of the cylinder block is arranged at an upper part of the crank case, said cylinder block and/or said cylinder head are at least partially exposed to the outside of the vehicle, wherein the crank case comprises a first side cover lid attached to the crank case to constitute an outermost portion of the crank case in width direction of the vehicle, said first side cover lid is exposed to the outside, wherein a cover means comprises at least a first cover portion arranged under said first side cover lid, said first cover portion comprises a side section (9a1) that extends in a downward direction to cover a space under the crank case and intersects an imaginary plan that contains a road contact point of the front wheel and outermost portions of the footrests (3a,3b) in width direction of the vehicle, and the crank case comprises a second side cover lid attached to the crank case to constitute an outermost portion of the crank case in width direction of the vehicle, said second side cover lid is exposed to the outside, and the cover means comprises at least a second cover portion arranged under said second side cover lid, said second cover portion comprises a side section (9b1) that extends in a downward direction to cover the space under the crank case and intersects the imaginary plan that contains the road contact point of the front wheel and outermost portions of the footrests (3a,3b) in width direction of the vehicle, wherein the first side cover lid and the second side cover lid are exposed to opposing outside of the vehicle and constitutes outermost portions of the crank case in width direction of the vehicle, and the cover means comprises a third cover portion arranged in width direction of the vehicle and connecting the first and second cover portions (9a, 9b), said third cover portion intersects the imaginary plan that contains the road contact point of the front wheel and outermost portions of the footrests (3a,3b) in width direction of the vehicle, front end sections (9a2, 9b2) of the first and second cover portions (9a, 9b) are extending further forward of the vehicle than a central section (9c1) of said third cover portion, characterised in that the three cover means (9a, 9b, 9c) are provided as separate elements, which in combination form the cover means.