I'd gladly loan it. I would just take a deposit, say 2X what the bike is worth. And when it was returned, adjust the deposit for any damage/issues. If he wants use of the bike for free, ask if you can borrow some of his cool cameras, or his car for a road trip to Vegas, or whatever. Movie companies are famous for charging a lot of money to rent movie props to themselves, with another charge when the item is returned, plus repair costs, etc. Nothing free in the movies.