Re-building any Honda engine will benefit from the fitting of new valve guides. Even the smallest amount of wear will allow engine oil into the combustion chamber, reducing performance and leaving a smoky plume from your exhaust. Very un-Honda like! These are genuine new Honda parts, and considering what they do, and the precision engineering used to make them are very reasonably priced indeed! *You may wish to order valve stem seals to go with these? *Genuine Honda part *Manufactured to original tolerances *Helps stop your 'Four' smoking, even if you have not stopped!