Track not kept in a good state of repair (3,4)
I believe the answer is:
run down
'track' is the definition.
(running down is a kind of tracking)
'kept in a good state of repair' is the wordplay.
I cannot really see how this works, but
'state' could be 'nd' (abbreviation for North Dakota) and 'nd' is found in the answer.
'of' could be 'o' and 'o' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
'not' acts as a link.
Can you help me to learn more?
(Other definitions for run down that I've seen before include "Dilapidated - denigrate (3-4);" , "exhaust?" , "slate" , "Knock" , "A detailed analysis, being weak and exhausted" .)