def38
Platinum Member
The oil in air cooled engines can go a long time. No coolant contamination. Long as the carb doesn't flood oil can be near lifetime service. A change doesn't hurt once in a while but there is no magic pixie dust in any of it.
Pixie dust, no, but todays engine oils are full of additives that extend engine life, improve economy, keep deposits at bay and reduce wear. It is widely understood that todays engine oils are head and shoulders above the engine oils of just 10-15 years ago. I have several large displacement gasoline engines that are air cooled and need high spec oils for protection. If I were to avoid oil changes, camshafts, valve actuating gear, timing chains and timing chain tensioners would need early replacement. Also, air cooled engine oils providing a large percentage of the engines cooling. I would deem it bad practice to avoid oil changes at reasonable intervals.
I have a colleague who rides an air cooled BMW boxer twin motorcycle of over 1000 cc displacement. The BMW is 1996 and has well over 500,000 miles on the original engine. He uses Mobil1 synthetic engine oil and changes it regularly.