As long as the bike is insured in your name, they can ride it.
Problem with that is that if they wreck and decide to walk away, you're left holding the insurance bag. That's why you get the cash up front *before* the test ride to alleviate that risk, but you can't entirely eliminate it as if it somehow ends up "on record" (The guy dumps in traffic, police attend, and there's now a paper trail) it can end up with a ding on YOUR insurance as a result.
The second problem with that is if they wreck and someone gets hurt (them, or a pedestrian, whatever), or they hit someone elses property, you're also left holding the bag on the insurance side.
Anytime anyone operates a vehicle under *your* insurance, you are taking nearly 100% of the risk.
For me, what I do is this.....
- Buyer comes looks at bike, hears it run in driveway, plays with whatever they want to play with...in driveway.
- If they ask for a test ride, I tell them I'll ride it up and down the street for them, go through all the gears up and down, start and stop...whatever they want to hear and see.
- If they decide to buy, they come with the payment AND their own insurance slip. Beforehand, I call and suspend my own insurance (important) before the test ride/completion of sale. I then have them sign a bill of sale that the sale includes a test ride after the legal ownership transaction, and if for some reason they are not happy with something the deal can be cancelled IF the bike is returned unscathed. If they're happy, sign ownership, shake hands, done deal. If they decide to exercise that option for some strange reason, we shake hands, I hand the payment back, they walk away. No harm, no foul, aside from a tiny bit of gas used.
Realistically nobody who's gone so far as arranging the insurance at this point and handed over payment is going to back out of the deal, but it reassures them that the option exists if they to get that test ride and they find something they don't like, and shows that you've nothing to hide. I always explain why I choose to do it this way and any serious realistic buyer is fine with it.
It's a PITA, but it removes all liability for me. If they ride away during this stage and crash/wreck/whatever, it's on them - they technically own the bike at this point on paper, and the insurance liability is all in *their* name, so you don't get mixed up in any insurance nightmares that might result.
And I've never had anyone back out of the deal once reaching that point.