Right for one motoring club to hold races in sporting event (7)
I believe the answer is:
regatta
'sporting event' is the definition.
(I've seen this before)
'right for one motoring club to hold races' is the wordplay.
'right' becomes 'r' (common abbreviation).
'for one' becomes 'eg' (both can mean 'for example').
'motoring club' becomes 'AA' (the AA, Automobile Association).
'to hold' means one lot of letters goes inside another.
'races' becomes 'tt' (Isle of Man Tourist Trophy races).
'aa' placed around 'tt' is 'atta'.
'r'+'eg'+'atta'='REGATTA'
'in' is the link.
(Other definitions for regatta that I've seen before include "Yacht-race event" , "It could involve a lot of rowing" , "Aquatic activity" , "which may involve eights" , "Racing boats" .)