Your sentence is technically correct. A better, more natural way to say it would be, "A motorcycle was going very fast" or "The motorcycle was going very fast".
For motorcycles and bicycles, when we are talking about a person (I, him, her, etc...) on a motorcycle, we say, "He was riding the motorcycle" or "She was riding the motorcycle very fast". Typically, we only say "drive" when we are referring to a 4 wheeled vehicle. You can say "He was driving the motorcycle very fast" and you will be 100% understood, but it won't sound 100% natural and is not the customary way of saying it.
Hope this helps!