I have a motorcycle that is 100 years old in a couple of years.
I ride it more hours per year than most mowers run, it has no filter and still on std bore and original bearings & bushes ( mind you some of them are a little past due for replacement ).
Most motorcycles of the 50's & 60's had next to no external filters, ran around 10:1 compression, did 6,000 to 10,000 rpm and ran quite fine, provided you change the oil.