The top speed of a KTM 125 motorcycle can vary depending on various factors, including the model, rider weight, road conditions, and modifications (if any). Generally, the KTM 125 motorcycles have a top speed ranging from approximately 80 to 100 km/h (50 to 62 mph). It's important to note that these figures are approximate and can differ based on specific circumstances. The manufacturer's specifications and user manual for a particular KTM 125 model can provide more precise information about its top speed.