Sounds like a bad idea to me. Lots of reasons, but then there is the friend thing.
If something were to break- like say a shifter- after you sold it then you might be guilted into fixing it. Or feeling like you should. If you sold it to a stranger and a month or so down the road something goes wrong, well not really your problem. It was a used bike.
I'm not in any way saying that there IS or may BE something mechanically wrong with the bike, but it is used. Stuff happens.
I'm still trying to sell my road bike, but when the boyz were doing a tune up on her a shifter broke. I had no idea that it was about to break, the bike always ran flawlessly. But it did. Of course I'm glad it did it before it went to a new home, but it just goes to show that stuff can happen.

I just always think that when selling something mechanical, it's best to sell to a stranger. They understand the "as is" clause better than a friend would. AND you won't be upset if the bike gets altered or (gasp) abused in any way.

My husband sold his old Santa Cruz through our shop. He was explicit when he told the guy "It's an old bike with old componets, so it's AS IS".
Well the guy has been back TWICE now to complain about the brakes and the shock.
I told him "no more used bikes through the shop!" OY!!!