Motor-racing company accepting a second disaster (6)
I believe the answer is:
fiasco
'disaster' is the definition.
('fiasco' can be a synonym of 'disaster')
'motor-racing company accepting a second' is the wordplay.
'motor racing' becomes 'fi' (FI resembles Fa, Formula a).
'company' becomes 'co' (abbreviation).
'accepting' is an insertion indicator.
'a second' becomes 'as' (I've seen this in other clues**).
'fi'+'co'='fico'
'fico' enclosing 'as' is 'FIASCO'.
(Other definitions for fiasco that I've seen before include "Farcical disaster" , "A ludicrous failure, a shambles" , "Complete disaster" , "Ignominious result" , "Utter failure, debacle" .)