AITA for refusing a refund on a bike I sold as-is with a video of it running?

2009 bandit, 41k, sold as-is for $2,100. buyer rode it home 30 miles. i sent a walkaround video the night before including the cold start. four days later.
What People Are Saying
as-is, walkaround video, cold start on camera, told him to bring a mechanic. there is no version of this where you owe him anything.
honestly if he'd said "hey this sucks, can you help me out with $200" i'd have thought about it. "you knew" ended that.
"I'm not saying undo it, I'm saying you knew" - he wants the moral win AND the money, he just hasn't picked which one yet
a 2009 with 41k for $2100 is a project price and he knew it when he handed over the cash
Is it rude when a cashier starts scanning the next customer's items before I've finished bagging?
should i take a six week guiding job or stay home and risk the back taxes
AITA for leaving a nastier note back on the truck that boxed my van in overnight?
should i quit my job at the shoe store to go all in reselling flips
@rusty_ridesfree+79
300 miles in four days on a bike he says was leaking from day one. you don't ride a leaker 300 miles, you park it.