Goudrons said:

The old Air Cooled were robust rather than totally reliable.

Simplicity at it's simplest, they didn't really breakdown as you'd have it running again with a bit of a fettle.

As Portland states they needed a certain amount of care, but they were pretty under stressed engine compared to most engines at the time.
They were designed to run flat out all day but gave up little power.

My Dad's old Type 2 Camper went 45 years on it's original engine with just basic care. (which involved a screwdriver, a hammer and some swearing)

Considering it was just a 1.6 litre, made around 50 hp and had to drag a camper van conversion with six passengers (and a lot of duty free) around Europe year after year, it didn't really have an easy life, but we never broke down, though there were a few niggles, mainly due to a dodgy carb and poor fuel in the Balkans.

I guess a lot ended up like Trigger's Broom.
It's so easy and cheap to keep them running, pistons and cylinders, heads and so on can be swapped in situ for little money.

One of my favourite scenes. (that and the Orgasmatron scene)
https://www.youtube.com/watch?v=Ctin21yrfcA

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