The most common fastener on most motorcycles is the familiar “hex cap screw,” which has a six-sided head. Also often encountered is the Phillips socket-head cap screw, which has a cross-form socket into which a Phillips screwdriver fits (there are different standards here, such as the JIS, so you’ll find some drivers fit better than others). Another common fastener is the stud, which is a length of rod with threads on each end. In many engine designs, a set of long studs with one end screwed into the crankcase with the opposite end projecting upward through the cylinder and head.(…)
