Hi ive got a Vitesse built by my grandad so it has some parts swapped between different triumphs but whilst driving it the breather valve lid fell off and I've been having problems with it ever since as the first time i put to the bottom of a can on top but it kept the diaphragm from moving so im double checking that i need to make it fit over the whole thing or the inner rim. Also is a whole in it necessary. In the photo i tried recommended by someone but let in too much air.