GL 1200 1984 engine advise wanted

Hi Kev and welcome to the forum. You will find all the help you need right here....
There is a drop down menu at the top right of the screen starting at "Quick links", down to "GWF links" where you will find most of the info you need there to start with and get to know a bit more about your iconic motorcycle.
There is much information on this site and indeed the internet as a whole, and if there is anything specific we can help with just post, you will get replies from many knowledgeable members.
Cheers,
Peter.

Welcome to the forum.

I believe most if not all GL1200's destined for markets outside the USA did not have the secondary air ports in the heads.