[oldwing 1]

Is the factory radio on Canadian editions able to have Sirius radio installed. I can’t see the hookup spot on the radio under trunk and seat area

 

[Farmguy]

There is no 'Honda' solution for XM/Sirius on a Canadian 2018 Goldwing.
(because, as you've discovered, the audio unit does not have the provision for hook-up)

2019's are reported to have the xm capable version of the audio unit.