[puddleglum]

What size of motorcycle are you starting with? The size and weight of the bike is going to determine how much power you need. I've been looking at Golden Motor stuff as well but shipping costs seem fairly high and you will want to check into what US customs will charge you on imports from China. You want those costs included in your budget. Also, you haven't mentioned a charger or a BMS. You will need a charger designed to work on Lithium Ion batteries. I think Lithium is the way I would go if I was building a light bike, but I think you had better raise your budget to at least $2500 or more. I'd love to see you prove me wrong though. Have you considered the Lithium packs that they sell for E-bikes? I think they might work pretty well if you linked a few together to get the right pack size.