Went to see a fellow motoring enthusiast to give a bit of a hand (10)
I believe the answer is:
metacarpal
'a bit of a hand' is the definition.
('metacarpal' is part of 'hand')
'went to see a fellow motoring enthusiast' is the wordplay.
'went to see' becomes 'met' (meet can mean to go to see someone).
'fellow motoring enthusiast' becomes 'carpal' (I can't explain this - if you can you should give a lot more credence to this answer).
'met'+'a'+'carpal'='METACARPAL'
'to give' acts as a link.
(Other definitions for metacarpal that I've seen before include "part of body" , "Bone in hand" .)