i agree, that guy doesn't deserve a bike. besides the drinking problem, if he's already suing someone over a bike, i'd stay far away from a guy like that.
all the bikes i've sold, i make sure i'm selling them to reasonably competent people. i also tell them they're dangerous, prone to breakdowns, and sold as is. i explain all the laws, and tell them i've got no money anyway, so suing me won't get them much.
not exactly legally binding, but since it's a private sale, and i don't represent myself as a company, my buyers know they'd be better off suing the city over potholes or whatever the cause of a crash could be.
i also don't sell junk bikes. every one i've sold has been ridden by me for a while, and i wouldn't sell anything i didn't have faith in.
there's an old guy i run into all the time who's offered me some pretty outrageous prices for my bikes (he offered me $2500 for my burgandy 24",) but he lost his license due to poor vision, a heart condition, and for just being old.
despite me telling him he still needs a license for a gas bike, he keeps bugging me.
i'll never sell him a bike, and told him to buy an electric from the store.
also, i've de-tuned and regeared a few bikes to slow them down, 'cause i'm hesitant to put a 40mph+ bike in a strangers hands.
i also think a waiver or disclaimer might cause more trouble. it gives the impression that you actually know what you're doing, and a good lawyer would probably rip you apart if any accident was due to any part on the bike failing, that you, as an "expert," shoulda known about.
good luck...
