A sequential manual transmission (like the type of transmission used on a fully-manual motorcycle gearbox) is a sort of non-synchronous manual transmission, which only allows the motive force to pick either the following gear (e.g., shifting from second to first gear) or the previous gear (e.g. shifting from gear mechanism to 3rd gear), in succession. This restriction avoids accidentally selecting the incorrect gear, however, it also prevents the driving force from deliberately “skipping” gears.

The clutch during a sequential manual transmission is just needed when going from a standstill (i.e., stationary; neutral) into 1st gear, after that, it’s clutchless shifting since the gears are forced into place via the dogs. This contrasts with a standard Manual transmission, which uses synchromesh for smooth gear shifts. The employment of dog-clutches (rather than synchromesh) leads to faster shift speeds than a manual transmission.

On a sequential manual transmission, the shift lever operates a ratchet mechanism that converts the fore and aft motion of the shift lever into rotation of a selector drum (sometimes called a barrel) which has three or four tracks machined around its circumference. Selector forks are guided by the tracks, either directly or via selector rods. The tracks deviate round the circumference and because the drum rotates, the selector forks are moved to pick out the specified gear.