When I built my Victor replica I used a Series D cap on the inlet as per the prototype Victor but it breathed out a lot of oil. I put a Mac Reed one way ball breather on the magneto cover but was unable to fit the baffle arrangement onto the exhaust cap because of the fairing mounting so I simply fitted a large bore pipe (3/4") right out to the back of the cowl. Apart from a loud "plop" from the nylon ball when kicking it over it breathes out no oil or vapour at all! I have made one for Andy Hugginson's Comet and fitted it without the baffle and his doesn't breathe out any oil either. My advice would be to try it without the one way valve and see. I believe that the Ron Kemp breather just uses some sort of gauze in there and no one way valve but I may be wrong. Perhaps Russell could confirm this.
Brian
Brian
