OK, this is where I expose myself to all your banter. Some years ago I bought a small 100cc motorbike for commuting/fun. It was about this time that 4 star petrol was being withdrawn. Well my little bike was about 10 years old and I wondered for many months about how it would manage on lead free fuel. It wasn't until I came to check the valve clearances that it dawned. It was a 2 stroke engine.
John