Re-building your engine? If yes it is worth renewing this part, as it will help restore performance by delivering more accurate valve timing, and of course the engine will run much more quietly as well. Whilst carrying out your engine rebuild, you might like to browse the CMS web site, and see first hand the vast amount of spares and service items we stock for these machines listed below. Please check the application list to ensure you specify the correct part number for your machine.