yes you could make money. there are always people that want custom stuff, but they dont want or know how to do it. how do you think custom car and motorcycle shops work? i know pleanty of people that would walk into a shop and buy a new rebuilt 2 stroke. they are becoming more and more rare, and just wait the value on all of them are doing to go up.
i know what you are thinking. parts. if they get a dealer account with different manufactures you get dealer cost. not what we would pay. you have to think of it like this. when you buy something at a shop, or store (unless they are giving you their dealer price) you are paying 25%-150% more then what they paid for the items you get.
for instance i just bought a holding clip and 2 bolts for the front sprocket for my wifes blaster. dealer cost was $0.30 for each bolt, and $1.00 for the holding clip. i paid $75.00 per bolt, and $3.50 for the holding clip. not to mention $5.00 for freight. so pretty much the shop i went to made $3.40 just to type the information into his computer, and call me when the parts come in.
i know it seems like they are not making that much money on an item for that, but think about when someone orders a-arms, a big bore kit.
bottom line is if you are doing good custom work people will buy it. im sure he would also rebuild a 2 stroke that you owned.
just look at Orange County Choppers, started in a garage. not they have $100,000 production bikes.