The bike behind it is the Yamaha RD500.
The exhausts on the RG shown are designed purely for power and not aesthetics. The tech was a Nazi invention to help improve the efficiency of 2 stroke engines, and was refined further during the cold war
http://en.wikipedia.org/wiki/Expansion_chamber.
Totally different from a 4 stroke engine. They are long and spindly as the expansion bit needs to be a certain distance from the engine to give max efficiency (whilst the total tuned length needs to be another length to give a broad spread at a given RPM (too high and the pistons fall apart)