Overhaul man in black Bugatti and contest ends (5)
I believe the answer is:
Here is my best explanation:
'overhaul' is the definition.
(I've seen this before)
'man in black bugatti and contest ends' is the wordplay.
'man in black' becomes 'ref' (football referees often wear black).
'bugatti' becomes 'i' (I can't justify this - if you can you should give a lot more credence to this answer).
'and' is a charade indicator (letters next to each other).
'ends' indicates one should take the final letters.
The last letter of 'contest' is 't'.
(Other definitions for refit that I've seen before include "Repair or re-equipping of a ship or shop?", "Restoration and repair of equipment etc", "Do repair job", "Repair - renew", "Equip for further use", "Overhaul (ship's equipment)", "Replace or repair equipment as part of a general overhaul", "Refurbishment (of ship)", "Renovate (a ship)" and "Replace equipment in (a ship, etc.)".)