How to tell what cc Apex mini motor is from the outside?

[Three-foot]

Evening,
Wondering how one might tell if an Apex mini is a 90cc or 100cc from the outside? Is there any stampings on the cylinder you can look at?
Thanks,
Three Foot

[robinson446]

look at the jug if 90 cc it will say 89 if 100 it will say 98 something i think