Head Breather Replacement.......

[Deimus]

Just in case you were wondering, I cured my blow-by issue by installing a new 1250 kit from NRHS. These 1250 jugs have thicker iron sleeves to improve the cylinder integrity. My old bored 1212 cylinders were not remaining round based on the wear marks of the pistons when I removed them. There were places in the cylinders without any sign that the pistons were even touching them there. The honing hash marks were still visible in those places. This is an issue discussed on the NRHS and Hammer sites both when reading about stock cylinders.

[milmat1]

I would agree the rocker box leaks that have been a problem are likely related to the poorly designed PCV system. If everything worked right there shouldn't be standing oil in that area and there would be no positive pressure to push the oil out. We could even go back far enough to say the Aluminum Cyl's and there high level of distortion are contributing to the problem. ( as Deimus pointed to).

And too Guy's I wasn't intending to rehash the whole venting problem as Deimus has covered that problem very completely in his thread. And I would suggest that everyone read that thread. (Very Informative) I just wondered why nobody had made a replacement for the factory breathers. And the answer seems to be "Why Bother" because the location of the breathers are as much of the problem as the breather design is..


BTW, Didn't we once decide that the hole in the banjo bolts were too small as well...

Anyway Thanks for the great input and information everyone !!

[mick42]

Buell has PCV's in thier XB rocker covers. My 05 1200R use to always blow out a load of crap at high speed hiways runs until I changed the rocker covers and added an EBOC.
Not an issue anymore. There are a few threads on the forum about this mod that include all the HD/Buell part numbers needed. Cost me just under $100.00 for all the HD parts on-line.
The big plus for this setup is getting rid of all the breather tubes around the Mikuni and no more breather bolts.

[milmat1]

Found something interesting. While examining the breather units I thought WTF I just blow in it each direction, and to my suprise air did flow both ways. (In the New Ones).
We were thinking that one of the most important features of this type of PCV valve was to limit the airflow to Only Out. But for whatever reason they have this small hole maybe 1/32" drilled to bypass the umbrella. If I cover the hole then it works as I expected Blow one way but not the other. But left uncovered this little hole allows air to flow both ways. WHY? Why have an umbrella valve acting as a check valve then have a bypass right beside it ?? Make little sense to me.
Of course the tiny hole will not in any way flow as much air as the umbrella area will but still I dont dig why its there....??
I was tempted to plug the hole just to see what happened but my better judgment got the best of me again.....