This is just no way to treat a motorbike, and parked in a tow zone, no less. Maybe an unsuspecting snow plow will come along in the middle of the night and put it out of its misery?
In any case, I'm guessing an '80's 450-ish HonKawYamaSuz.
UPDATE: I submitted this to Abhi at Bike-urious.com and it didn't take long for a reader to correctly guess that it's a 1982 Kawasaki 440 LTD.