When I sold my '99 Katana 750, the first guy who showed up to buy it was a skinny 16 year old with his mom and a friend of theirs who supposedly knew about bikes. He asked me if he could test drive, and of course I was scared stiff letting this kid take my always-babied, mint-condition bike off my driveway without it being paid for.
I ended up saying that this guy could check the bike out, they could start it up and check whatever they wanted, but no test ride. I wrote on the bill of sale that if he brought the bike back within an hour and with less than 30 km put on it, I would take the bike back. This was so he was assured he wouldn't take it up to 100km/h and have it wobble like crazy or something, and of course I knew he wouldn't find anything wrong with it.
It was just something I kind of thought up when they were there, and they seemed to go for it.
The reason I ask of course, is what happens if the guy taking your bike out for a test ride drops it? It would be a pain to have to sue some guy for the damages, or maybe they'd only offer up the deductible, which would work but of course hike your insurance rates.
But then again, now that I might be on the other side of the sale, I would have a hard time buying a 3-4 year old bike without seeing that it hangles ok, and there isn't a misfire or hesitation at certain rpms, or that it wobbles like crazy over 80km/h, or something like that.
So how do you guys handle the used bike test ride? Ask for the cash up front and if they dump the bike, they just bought it? Ask for a huge deposit?
Just wanted to hear some opinions before I go check out a few used bikes I have my eye on.

Thanks!