How fast does a 50cc moped go with 70cc kit on?

With a 70cc kit, a 50cc moped can reach speeds of around 40-45 mph (64-72 km/h) on flat ground. However, the actual speed will depend on several factors, including the specific model of the moped, the terrain, the rider's weight, and the gearing.

It's important to note that installing a 70cc kit on a 50cc moped may require modifications to the engine, exhaust, and other components, and may also affect the moped's handling and safety. It's recommended to consult with a qualified mechanic or moped enthusiast before attempting such modifications.