In mho, your in an awesome position to do it. The cost of scooters is skyrocketing and is the only real fiscal competition. You have the space, tools and customer base already! Even if you were only to charge time and cost, it is still productive, billable hrs. (Not that I am suggesting you do that) With the added bonus of not having a shop next door with the same product competing by price. If you are the only game in town, and your price for a kit or a completed bike are not price gouging, it is a very viable business opportunity. Many dealers will give you a volume discount when you buy a certain amount of kits at the same time.
I am working on a "Build your own motorized bike class" for a group of local vets. It is not for profit, but works the same as for profit "build your own.." any thing classes. The people taking the class buy the product and you show them how to assemble and use it. Just a thought.
Best of luck!!