Try port shortly before (4,1,2)
I believe the answer is:
have a go
'try' is the definition.
(thesaurus)
'port shortly before' is the wordplay.
'port shortly' becomes 'have' (I can't explain this - if you can you should believe this answer much more).
'before' becomes 'ago' (I've seen this before).
'have'+'ago'='HAVE A GO'
Can you help me to learn more?
(Other definitions for have a go that I've seen before include "Try (to help stop criminal?)" , "Tackle criminal" , "Words of encouragement" , "Make an attempt" , "Intervening to stop a criminal (colloq,)" .)