The slowest bike that would still be considered a motorcycle typically depends on the legal definitions and regulations of different regions. In many jurisdictions, a motorcycle is defined by its engine displacement, rather than its top speed. However, there is no universally agreed-upon threshold for the slowest motorcycle.
In general, motorcycles are designed for higher speeds and typically have engines with larger displacements to provide sufficient power. The slowest motorcycles on the market often have engine displacements around 125cc or lower. These motorcycles are often referred to as "small-displacement" or "entry-level" bikes and are popular among beginner riders or for commuting in urban areas with lower speed limits.
It's worth noting that the top speed of a motorcycle doesn't solely determine whether it is considered a motorcycle. The engine configuration, design, and other technical aspects also play a role. Additionally, certain electric motorcycles with lower power outputs might have relatively low top speeds but still be considered motorcycles due to their design and intended use.
Ultimately, the definition of a motorcycle can vary depending on the jurisdiction and specific legal requirements, but motorcycles with engine displacements around 125cc or lower are generally considered the slowest motorcycles while still falling into the motorcycle category.