1978 valve cover questions

[rabbie6]

1. Are all the 70’s CB750 valve covers the interchangeable?

2. There is a tiny circular hole to the breather port in the centre for pressure release tube back to air filter - correct?

The cover I have has a broken section of the wall allowing oil into that are also - about 1/4” by 1” - I suspect the oil can still return to the vale’s but isnt the idea that only the little hole allows for pressure to release into that chamber?

I bought a second cover and it has 2 wall sections broken out!

I have been searching for ine that only has the single round hole but so many show what look like larger square factory cutouts!

What am I missing about the covers and this pressure release area…?

 

[dirtdigger]

They are all interchangable. you have to have windows so crank vents to the upper chamber of the valve cover. I never payed much attention but these are two of mine, Ill have to check my box of other ones to see what they look like. Post a picture from the top of the valve cover but the holes in yours shouldnt be a problem and are there for a purpose.