I don't understand what is meant in the owners Manual when they say rear engine fixing screws is this the rear motor mount bolt? And what are the swivel arm bolt clamping screws?then they say tap with moderate force with a plastic hammer on the spacer. Can someone explain this in American terms. This is the note under removal and refitting of the engine. I'm just replacing the bottom front chain roller that the rear motor mount bolt goes thru. Any help would be greatly appriciated