Incentive to get back into motor racing (6)
I believe the answer is:
carrot
'incentive' is the definition.
(thesaurus)
'back into motor racing' is the wordplay.
'back' is a reversal indicator.
'into' indicates the answer is hidden within the clue.
'torrac' can be found hidden inside 'motor racing'.
'torrac' in reverse letter order is 'CARROT'.
'to get' is the link.
(Other definitions for carrot that I've seen before include "veg" , "orangey colour" , "Tapering vegetable" , "Incentive (but not the stick)" , "The vegetable for persuasion" .)