Just came from the local dealer and checked it out. I found 2 out of 8 with the breather hose already installed from the factory. The ones with the breather hose had 5/19 build dates. It’s very discreet and hard to see unless you feel for it with your hand. I just ordered a kit and I’m installing it myself to avoid H-D’s charades.

 

I'm not educated about engine internals, but a naive question: A low pressure on the crank seal caused by pistons rising. Wouldn't there also be a high pressure caused by pistons falling?

 

To me that would imply that something in the crankcase ventilation system is holding vacuum in the crankcase instead of venting properly.
It is my understanding that the EPA mandated that crankcases can't be ventilated directly to outside air.
Perhaps someone with more understanding of the M8 pcv system can chime in.

 

You were able to buy the kit straight from the dealer? Every post I've seen said it wasn't for sale to the public yet.

 

The crankcase is vented into the air cleaner. My understanding is that there isn't a pcv.

 

for all intents and purposes the breather bolts are the HD version of an automobile pcv..same thing only different I guess

 

Exactly what I'm saying above. The primary may be dropping in pressure, but it is not the reason for the drop in pressure - i.e. it is not creating the vacuum, it is merely a vessel that air is being sucked from, from somewhere, which I suspect is as you said, the crankcase.

 

Can you let me know what dealer let you order one?

 

Yes. If you're looking at pressure inside the crankcase, the pressure decreases as the piston rises. This means the crankcase seal will be sucked in toward the crankcase as the piston rises. If there is a leak around this seal, the air on the primary side of the seal will be sucked into the crankcase. HOWEVER, this is where we need more details:

1. If the primary is sealed off completely from the transmission and the atmosphere, a very minuscule amount of air would pass through the seal into the crankcase to balance the pressure between the crankcase and primary.

2 .If the primary is sealed off only to the atmosphere and was open to the transmission (i.e. a sloppy tolerance between the clutch pushrod and its passage), the air that was just sucked from the primary has to be replaced, which would come through the clutch pushrod passage, bringing with it transmission fluid.

3. If the primary is sealed off only to the transmission and was open to the atmosphere (i.e. a tight clearance between the clutch pushrod and its passage, and with a primary vent installed), the the air that was just sucked from the primary has to be replaced, which would come from the atmosphere.

4. If the primary is open to both the atmosphere and transmission (i.e. a sloppy tolerance between the clutch pushrod and its passage, and a primary vent installed), the air that was just sucked from the primary has to be replaced, which would mostly come from the atmosphere, given the cross-sectional area for the atmospheric opening is greater than the cross-sectional area of the transmission opening.

Note: I didn't proofread - forgive me if a made an error.

 

Love the conversation. Just want to point out that the breathers (umbrella valves) in the actual heads work as a PCV. - same job, same effect.
They are one way, which enforces the hypothesis of the possibility of there being crankcase vaccum acting on the crank seal.