So, I left the key in and the bike on last night... dumb me, picked up the mail and messed up when I stopped. Killed the motor by putting the stand down, and then the *usual* procedure is to turn off the key, pull it out and drop it in my glove. Forgot, and the battery was dead flat this morning... couldn't even roll-start it. (The issue was exacerbated by the fact I had 98 octane fuel in an old Bandit, which meant it needed choke to start.) Got a lift in to work, and when I got home this evening jump started it (easily and quickly) with the car and then went for a long ride. Used up the last of the 98 and filled up with 91, and it started fine at the servo. Was *very* careful to get the key out when I got home! I was happy to leave it at that, but checked a couple of old threads here to see whether it was dumb to jump start a bike (old, carburetted) with a car. Didn't find anything on that, but found lots of opinions that once a battery has been flat it's stuffed and should be replaced. Doesn't seem to make sense to me: it's not an old battery and it was perfect before my stuffup. Guess I'll see how it travels over the next few days and see what's up.