I realize there are laws, but do you think NYPD's finest really give a rat's A$$ about a neglected rusting bike? They're more interested in recovering stolen iPhones. Plus, they don't allow cars to be parked/stored on the street in the same location for more than a few days, are bikes different?
It's probably more of a Sanitation Dept. issue. After six months, I would remove the bike, put a weatherproof sign up for contact info if someone is missing bike. If no one contacts you after two months..........................