Bearing removed from the piston or throttle (5)
I believe the answer is:
north
'bearing' is the definition.
(a compass bearing)
'removed from the piston or throttle' is the wordplay.
'removed from' indicates the answer is hidden within the clue.
'NORTH' is hidden in the letters of 'piston or throttle'.
(Other definitions for north that I've seen before include "To the left of one who is facing east" , "Former statesman" , "Pole" , "He let America go" , "Bridge position" .)