Brave types appear outside for one statement before risky venture (4,4)
I believe the answer is:
here goes
'statement before risky venture' is the definition.
'brave types appear outside for one' is the wordplay.
'brave types' becomes 'heroes'.
'appear outside' is an insertion indicator.
'for one' becomes 'eg' (I've seen this in other clues).
'heroes' placed around 'eg' is 'HERE GOES!'.
(Other definitions for here goes that I've seen before include "I'm about to start" , "Words spoken before start of rash action?" , "Informally, I'm about to begin" , "I'm starting" , "Let's begin!" .)