I work on a team that designed two electric motorcycles for the IOM TT Zero. Yes, it's a very different game from the gas races. Aero and energy storage on board are the primary concerns - the top team for the past several years has been successful primarily by packing on ~20-30% more energy than their competitors, so that they can go faster, for longer.
The TT is really an edge case, though, since it is such a long (38mi) and high speed course.