I recently bought my 82 GL1100I from the original owner. The bike was stored in his garage for the last 17 years. He recommended that I put synthetic oil in because he heard it gives better gas mileage among other perks, so I did. I haven’t put any miles on it yet because I’m waiting for parts that I ordered. Recently I was talking to someone who said these older Wings shouldn’t run synthetic oil, it might be damaging. Is that true? Should I dump it and go back to regular oil?