Took my bike in this weekend to get it looked over before my warranty expires and the tech said he noticed excessive crank case vacuum when he pulled my dip stick. He checked with a gauge and said it didn't return to normal readings until he disconnected the breather hoses from the breather bolts. He thinks the T connector for the external breather set up is too small. Anyone else have this issue before? I'm wondering if it's just due to my routing. I went up and over the heads, along the frame under the tank and then down the frame to so the filter sits under the regulator. Any thoughts guys?

 

I call bullshit on the mechanic

 

I don't care what anyone says, I don't care for the over the heads route, it defies gravity and there are some laws you can't ignore without enough pressure and that ain't enough pressure. I say re-route under to a common filter and you'll be golden.

Make sure your tubes and fixtures from the breathers are large enough inner-diameter but again, under goes with gravity and that's one thing we are all beholden to

 

I always thought the same thing about going up and over on the breathers. I was looking at the system pictured below, but felt like there wouldn't be enough pressure to push the condensation and oily crud out of the heads. I just kept thinking that this stuff would accumulate inside, and cause issue.

As far as the issues the tech reported, that just doesn't add up. The pinner holes in the banjo bolts would cause more restriction than a standard brass T.

 

I agree with SBM.

 

Maybe he meant excessive crankcase pressure? External breathers don't really pull any vacuum.

 

Done deal. I'll re route them tomorrow.