What age kids do you have to teach the lesson to?
What subject areas are being covered? I'm assuming a SOSE lesson???
What are your learning outcomes (what should the kids gain from the lesson) and what are the learning indicators? Are you trying to convince them to ride bikes (head in the cloads talk of freedom will not achieve much in terms of learning or teaching) or will it be a discussion of the benefits of motorcycles in society.
I would be inclined to focus the lesson on the pros and cons of motorcycles as a transport option. Enjoyment is part of that but there is also practicality concerns and safety concerns that could be discussed in relation to trafic conjestion and environmental (quality of life through less commuting time/polution) benefits. You can also talk about recreational motorcycling as a social activity and relaxation, both of which have enourmous mental health benefits.
It's a great topic (I would obviously agree with that). I'm not sure how you make it terribly relevent to students who aren't old enough to ride on the road. Will dirt riding be included?

Little black duck upsets easily. Reassure and give beer.