I've been iside many old saws of many brands. All had, what I would call, pathetic air filters. None of them were destroyed by fines. They all ran after some carb love and fuel lines. Some of those saws were definitely heavy use by homeowners that liked making saw dust. I'm sure many of you have seen way more than Myself messing with saws. I don't hear of fines ruining engines. Have any of you seen anything like that 500i picture? Thats a saw that was over heated with *s-worde oil in my opinion. Based on some of my test results with oils.