Loop breathers

[Guzzi relic]

Hi all. As I wait for parts (Gilardoni top end) I'm tackling some other things on my winter refresh list; '74 Eldo.
One is the breather box and I've read the Guzziology info as well as Greg Bender's site. I cut my breather box open as I didn't want to be fishing around for the flapper valve and I figure its an easy mig job to join it back together. (I'm not doing a restoration)

Mine has no screen, just wide open. My plan is to use a straight check valve, #28150560 from MG and remove the original flapper valve.
My question  is should I make up some sort of screen to fit half way up the box, at the seam, or should I leave it open?

Thanks.

Ken

[Antietam Classic Cycle]

All of them I've opened up had a screen inside, there to help condense oil vapor I'm guessing. I'd add a screen.

If the original "flapper" is in working condition, then I leave it. IMO, it's actually better than the ball type check valve since it can flow more air, there's less restriction.

[Chuck in Indiana]

All of them I've opened up had a screen inside, there to help condense oil vapor I'm guessing. I'd add a screen.

If the original "flapper" is in working condition, then I leave it. IMO, it's actually better than the ball type check valve since it can flow more air, there's less restriction.

No doubt.

[Guzzi relic]

All of them I've opened up had a screen inside, there to help condense oil vapor I'm guessing. I'd add a screen.

If the original "flapper" is in working condition, then I leave it. IMO, it's actually better than the ball type check valve since it can flow more air, there's less restriction.

Thanks for this. Thankfully I haven't ripped the flapper valve out yet.
Next question is; what sort of screen/mesh size would you recommend? I'd guess something coarser than window screen?
Although the photo on GB's site it looks pretty fine.

[Antietam Classic Cycle]

All of them I've opened up had a screen inside, there to help condense oil vapor I'm guessing. I'd add a screen.

If the original "flapper" is in working condition, then I leave it. IMO, it's actually better than the ball type check valve since it can flow more air, there's less restriction.

Thanks for this. Thankfully I haven't ripped the flapper valve out yet.
Next question is; what sort of screen/mesh size would you recommend? I'd guess something coarser than window screen?
Although the photo on GB's site it looks pretty fine.

Hmm. Good question. I don't remember how fine it was originally, it looks very fine. Maybe something like this?: https://www.mcmaster.com/85385t92

[Chuck in Indiana]

Chore boy.. (Guzzi content) 

[Guzzi relic]

I think I have a good idea of what to use. I'll check locally to see what's available.
Once again, thanks for the info.

(I had to google Chore Boy  its not a product that we see up here)

Ken