The first few bars not right to go within (4)
I believe the answer is:
into
'within' is the definition.
(I've seen this in another clue)
'the first few bars not right' is the wordplay.
'the first few bars' becomes 'intro' (I've seen this before).
'not' suggests deleting specific letters.
'right' becomes 'r' (common abbreviation).
'intro' with 'r' taken away is 'INTO'.
'to go' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for into that I've seen before include "To a point within - not I" , "Enthusiastic about" , "Two -- six is three" , "Keen on (informal)" , "Keen on, colloquially" .)