Petrol scooters can have different maximum speeds depending on various factors such as engine size, transmission type, design, and manufacturer specifications. Typically, a 50cc to 125cc petrol scooter can reach speeds anywhere from 30km/h (19 mph) to 110km/h (68 mph). Some performance-oriented and powerful petrol scooters with larger engines (e.g., 200cc to 300cc) may go as fast as 130-140km/h (80-87 mph).
It's worth noting that maximum speed also highly depends on factors such as the rider's weight, road conditions, terrain, aerodynamic factors, and overall vehicle health. In addition, most countries implement various regulations and speed limits for small motorcycles or scooters operating on public roads, so it's always advisable to stay within designated speed limits.