Use a synthetic oil.
Experiment with the oil filters. Don't just look for the best ADBV, sometimes a cheapo free flowing filter will work well.
Try the Amsoil or GC. These are the heavier
30wts.
And, IMO, most of my noisy chain'd engines quiet down on moly. Find an additive or an oil that has losts of moly. Torco, Redline, and Royalpurple have decent moly amounts. Some of the mineral oil and blends have a good moly dosage. Visit the VOA/UOA section for others!