[Bob50]

My suggestion is let them know that you will give them a 2 hour money back guarantee and do the deal up front without a test ride. If they bring the bike back within that time without any dents, etc, they can get their money back. However, if they bring it back damaged or not in the condition they left with it, they own it. You may have to draw up a contract and have it notarized. Check with an attorney to make sure your document is legal

What Jammer said! That's the best way to do it. No way would I let a stranger ride my bike.