This one thing keeps puzzling me. How is it that a bike can be happy even with a compression ratio as high as 13:1 when even the Enzo Ferrari has a compression ratio of "only" 12:1. What is it that makes bike engine special? Is it the capacity, the short stroke, the extremely over square dimension of the combustion chamber, what is it? Oh and how come they can run on regular petrol too?? For example a 600cc sportsbike with a compression of more than 12:1 can run with 91 RON comfortably when cars with 10:1 are recommended to use 91 or more. Also bikes with 9.5-10:1 can run on 87 RON, and they are carbed.

Sorry if this sounds noobish but any taikor can explain? Tried to search for info on the net but cannot find anything.

The Enzo can't use anything lower than 97-98 RON while scooters with 13:1 can use regular petrol. Why are bikes "comfortable"(as in no knocking) with a high compression ratio is what's puzzling me here.