I have a '88 and supposedly the Oil Drain Hose runs from the oil tank to a dead end on the battery tray. Stuck with a hose clamp. I can see it looking at the bike, Haven't done my first oil change in my onwership of the bike yet though.
here is the procedure with pictures and everything. I will be doing mine soon as well.
hope this helps.
EDIT: i posted and clicked the link and its not working, try copy and pasting it if its not working for you.