The top speed of a Kawasaki Ninja 650 can vary depending on various factors such as rider weight, riding conditions, and modifications to the bike. However, the stock Kawasaki Ninja 650 has an approximate top speed of around 130 to 140 mph (209 to 225 km/h). This is based on the manufacturer's specifications and should give you a general idea of the bike's capabilities. It's important to note that riding at high speeds can be dangerous and should only be done in appropriate conditions and within legal speed limits. Always prioritize safety and follow local traffic laws when operating a motorcycle.