The crankcase is still vented. Any positive build up of pressure is relieved. An exchange of air in the crankcase is not necessary or actually achieved in any appreciable way with the stock setup either. While some vacuum may be present, it is not required to prevent an over pressure condition.

 

Ok good info guess I should do this modd

 

It helps keep the nasty crap out of your cylinders.

 

Added a screen to catch any of the clamps I'm using in case they come off. I don't think it will block enough air to impede proper airflow but I'll be monitoring closely as I begin my riding season. If after a few rides with it on, even if it doesn't affect performance, I see that the clamps are staying put I'll likely take the screen off anyway.

 

Why don't you drill 1 more hole opposite your exit fitting and just run hoses through the backing plate? That's a lot of hardware to come loose and ruin a good motor.

 

Wanted to keep the holes in the backing plate to a minimum.
I doubt seriously anything is going to come loose. And that screen is heavy stainless. Nothing is going to get by it.

 

This is what my heart looks like with the bypass.

 

Hey, thanks for the belly laugh Mike

 

And more importantly - the throttle body.

 

I would bet if this was a big bore build and put on a dyno, that arraignment would certainly produce lower numbers than without. Maybe not significant, but something. Not criticizing the work, just commenting on how something as simple as the screen can alter the air flow and the hose that appears to be in the air stream. I too would suggest drilling an additional hole and relocating the right side directly out and connecting the two behind the back plate. It would also remove the uphill tube.