HOAs have a number of options to recover past due HOA fees, though it may be hard for them to recover the fees from an absentee owner. Eventually, if not paid, the HOA could place a lien on the property, which can cloud the title, and make transferring the property difficult.
It occasionally happens that an owner doesn't pay HOA fees when they get into financial trouble, and when a lender takes back the property through foreclosure, that lender is usually on the hook to pay the fees in order to make it possible to re-sell the property. Whether that lender has any legal right to later go after you, the prior owner, for the unpaid fees, I am not sure. I, too, would recommend that you talk to a lawyer.
Some lawyers will answer general questions like yours over the phone at no charge. If you aren't able to get your questions answered free, the Oregon State Bar offers a great service where they will connect you with a real estate lawyer for a half-hour consultation for $35. You can contact the bar association's Lawyer Referral Service toll free at 1-800-452-7636, or submit a request for an LRS referral online at: www.osbar.org/public/ris/lrsform.html
Best of Luck!