Ever since I put my heads back on my engine last summer I've been having some crankcase vent issues. I recently removed the complete rocker arm assy from the heads and here is what I found and am not sure what my solution should be. It appears that I have been venting my crankcase out the front cyl only, here is why.

The passage to vent the crankcase gases is different in the rear cyl then in the front cyl but the two rocker housing gaskets are the same??? The rear cyl's crankcase vent leaves the umbrella valve, vents thru a port that goes half way thru the rocker housing, then it crosses down from the housing into the cyl head's 2nd half of port and vents out that cyl head. The problem is that there is no hole in the rocker housing to head gasket to allow the downward crossover from the cover's 1/2 port to the head's 1/2 port.

The front cyl does not have this issue because the vent port is intirely in the head and there is no crossover needed between the housing to cyl head, thus no hole needed in the rocker housing gasket.

Thus my engine has been running with only the front cyl being crankcase vented which hopefully explains the crankcase backpressure and eccessive oil venting issues I've had.

I have an '01' Ultra TC. When I look at replacement rocker housing gaskets, they are both the same for the front and rear cylinders, even though the venting is different, which I think that the rear cyl gasket should have to have an extra hole in it or am I having another brain fart?

For what it's worth, I doubt if I would have ever noticed this problem if my engine was not turbocharged, requiring more crankcase venting then non boosted engines.

Thanks in advance for your input.[/align]

 

How do you like the turbo? What kind did you go with? Haven't run into the problem you mentioned but ran the S&S reed valve then plugged the bottom vent had no problems with venting on my 110 or the 127. I am looking at the RB turbo set up that comes with EFI and intercooler.

 

If I understand you the rocker box to head gasket , kind of a big one with rubber ridges running all around the place, is the one you are talking about?? If so,,,The gasket is the same for front and rear but it is put in one cylinder on one side and the other cylinder the other side. If you hold it in the light you can see, "Front", on one side. The other side is marked, "Rear". It happens, if so. I had to recheck myself a time or two. Lost focus.
If you get it wrong it blocks passages. You can still get one right and one wrong.

 

Thanks for the response but I've since figured out my problem. Too long to state here but briefly, I have one stock typeventversion of an S&S headon front cyl and another S&Svent version on the rear cyl. The S&S vent version normally requires an S&S rocker box to matchbut the previous engine builder modified the HD rocker box to work. Problem was is that he did not modify therocker box gasket to matchso the rearcyl's vent was completely blocked for 25000 miles. Keep in mind, thisbike was anEbay special, buyer beware.