Gear shift of a saddle vehicle comprising: a shift lever; a selecting element actuated through the shift lever; a selector drum connected to the selecting element and adapted to engage gears; a block device functionally connected to the selector drum and configured so as to be switched between: ∘ a first configuration, wherein the block device allows engaging a first gear from a neutral gear in a first change direction of rotation (Up), and ∘ a second configuration, wherein the block device inhibits the subsequent engagement of the neutral gear from the first gear in a second change direction of rotation (Dwn); control means of the block device configured to be actuated by a rider so as to define a third configuration, wherein the block device is disabled in order to allow engaging the neutral gear from the first gear in the second change direction (Dwn); wherein the block device comprises: - a stop element (141,141') constituted by a bushing comprising a tooth-shaped portion, mounted integral with the selector drum; and - a block element co-acting with the stop element (141,141') and adapted to switch between the first configuration, the second configuration and the third configuration; characterized in that the block element is mounted rotatable around a rotation axis (X-X) and comprises a first elastic element so as to take: the first configuration, wherein the block element is fastened to the tooth-shaped portion, corresponding to the neutral gear, allowing the selector drum to rotate in the first change direction (Up) to engage the first gear and the subsequent gears; the second configuration, wherein the block element is adjacent to, and touching, the tooth-shaped portion, corresponding to the first gear, preventing the selector drum from rotating in the second change direction (Dwn) to engage again the neutral gear from the first gear; the third configuration, wherein the block element is spaced from the tooth-shaped portion through the control means, allowing the selector drum to rotate in the second change direction (Dwn) to engage again the neutral gear from the first gear and to return to the first configuration. a shift lever; a selecting element actuated through the shift lever; a selector drum connected to the selecting element and adapted to engage gears; a block device functionally connected to the selector drum and configured so as to be switched between: ∘ a first configuration, wherein the block device allows engaging a first gear from a neutral gear in a first change direction of rotation (Up), and ∘ a second configuration, wherein the block device inhibits the subsequent engagement of the neutral gear from the first gear in a second change direction of rotation (Dwn); ∘ a first configuration, wherein the block device allows engaging a first gear from a neutral gear in a first change direction of rotation (Up), and ∘ a second configuration, wherein the block device inhibits the subsequent engagement of the neutral gear from the first gear in a second change direction of rotation (Dwn); control means of the block device configured to be actuated by a rider so as to define a third configuration, wherein the block device is disabled in order to allow engaging the neutral gear from the first gear in the second change direction (Dwn); wherein the block device comprises: - a stop element (141,141') constituted by a bushing comprising a tooth-shaped portion, mounted integral with the selector drum; and - a block element co-acting with the stop element (141,141') and adapted to switch between the first configuration, the second configuration and the third configuration; - a stop element (141,141') constituted by a bushing comprising a tooth-shaped portion, mounted integral with the selector drum; and - a block element co-acting with the stop element (141,141') and adapted to switch between the first configuration, the second configuration and the third configuration; characterized in that the block element is mounted rotatable around a rotation axis (X-X) and comprises a first elastic element so as to take: the first configuration, wherein the block element is fastened to the tooth-shaped portion, corresponding to the neutral gear, allowing the selector drum to rotate in the first change direction (Up) to engage the first gear and the subsequent gears; the second configuration, wherein the block element is adjacent to, and touching, the tooth-shaped portion, corresponding to the first gear, preventing the selector drum from rotating in the second change direction (Dwn) to engage again the neutral gear from the first gear; the third configuration, wherein the block element is spaced from the tooth-shaped portion through the control means, allowing the selector drum to rotate in the second change direction (Dwn) to engage again the neutral gear from the first gear and to return to the first configuration. the first configuration, wherein the block element is fastened to the tooth-shaped portion, corresponding to the neutral gear, allowing the selector drum to rotate in the first change direction (Up) to engage the first gear and the subsequent gears; the second configuration, wherein the block element is adjacent to, and touching, the tooth-shaped portion, corresponding to the first gear, preventing the selector drum from rotating in the second change direction (Dwn) to engage again the neutral gear from the first gear; the third configuration, wherein the block element is spaced from the tooth-shaped portion through the control means, allowing the selector drum to rotate in the second change direction (Dwn) to engage again the neutral gear from the first gear and to return to the first configuration.