As the Bullet is only of the 350 persuasion, weight of components is a bit of an issue. Pretty much everything that can be made of aluminium will be. In "Tuning for Speed" they even go as far as discussing drilling the centre out of the bolts on the bike to reduce even more weight.
A not inconsiderable saving in weight can be effected by waisting the bolts down to a diameter equal to bottom diameter of the threads, leaving a short parallel at each end to centralize the bolt or act as a register for the engine plates if required; alternatively, if the bolts have solid heads they can be drilled down the centre, as shown in the diagram, the hole (which must be accurately concentric with the outside) extending very nearly to the beginning of the thread. Far from weakening the bolts, this treatment actually makes them less prone to fatigue-failure and, if carried out consistently throughout the whole machine, a perceptible mass of excess metal will be eliminated.