No, the Yamaha TZR 50 is not the biggest moped in the world. In fact, the Yamaha TZR 50 is a small-displacement moped specifically designed for young riders or those with restricted licenses. It features a 50cc engine, which is a common engine size for mopeds in many countries.
When it comes to moped size, the term "biggest" can refer to different aspects such as engine displacement, physical dimensions, or overall power. However, in terms of engine size, there are much larger mopeds available on the market. Some mopeds have engine displacements ranging from 125cc to 300cc, offering higher power and performance compared to a 50cc moped like the Yamaha TZR 50.
It's worth noting that regulations and definitions of mopeds can vary between countries, so the classification of a moped and its engine size may differ depending on regional laws.