 Jawa motorcycles built for sidecar use, as opposed to solo motorcycle use, feature smaller 15 or 16 tooth gearbox sprockets (18 teeth on solo bikes), an attachment on the rear brake cable pivot arm for the sidecar's own brake cable to attach, a left footrest with an attachment for the sidecar brake cable to fit into and modified wiring loom at the rear of the bike with electrical power coupling for the sidecar's lighting and accessories.An adjustable friction type steering damper was fitted under the headstock on some machines, though this later proved to be unnecessary due to the good handling characteristics of the unit as a whole.This feature was occasionally fitted to the Type 634, Type 638, Type 632, Type 639 and Type 640 machines from 1974 to date.