Villiers Midget Gudgeon Pin

Hi All,

I am restoring a Villiers Midget engine which I believe, from the engine number (CYZ 40457), is a pre-war type. I understand that these engines had a floating gudgeon pin with a retaining disc to prevent the pin entering the transfer port. My engine has a disc fitted in a shallow counter bore in the gudgeon pin hole adjacent to the transfer port but there is no counter bore or retaining disc to hold the pin at the opposite end ie towards the exhaust port side. The exhaust port has a bridging section in the middle to prevent the pin entering from that side but without some sort of retention the pin could rub on the cylinder wall.
Can anyone explain exactly what the set up is with these engines?
Thanks,

Tom