As the owner of a 2005 Sportster 1200R, I need to ask the Buell owners who are familiar with their intake / top end systems this:
How does the Buell engine deal with crankcase pressure? Is it vented into the air cleaner ala the sportster engine? Or, does Buell have a more manageable system than the Sportster?
I'm looking for some good ideas here, and if I don't need to re-engineer the wheel...
BC

The XB breathers are different ( the rocker boxes are vented ) but the ones prior to XB just vented into the airbox/mouth of the carb, and were no better than the XL.

Some people vent it to the atmosphere on an XL, but you could install XB style rocker boxes and vent it like an XB (straight up.)

--Chris

my 2000 x1 was vented in to the air cleaner I changed to the XB style valve covers with PVC valves and route them under my seat were they have small K&N air filters on them. I have great pics of this on my web site but I havent had 15 posts yet so I cant post the link. I guess I need to start posting.

Oil does not just come out of the breathers normally.

My guess is you have a lean condition or spark timing is advanced or you have excessive carbon buildup (or all 3) that is causing detonation and unseating the rings causing blow by that is forcing the oil out.

You may not even hear the detonation as it may be happening at part throttle cruise and would be hard to distinguish from normal valve noise.

I think it’s a Buell problem I have never seen a Buell that didn’t do it. It’s just a bad design. Both of My X1s did it from day one off the lot. After taking them to the dealer over and over again with no fix in site I added a catch can. Then when they changed the design to the PVC valves I switch to that problem solved. Harley knew it wasn’t good design are they wouldn’t have changed it.

I would like to add a 4th contributing factor to the oil blow-by problem. Oil Temperature. The Harley manual states that you should use 60W oil in ambient temps 80 degrees or over. Buell's have a smaller oil tank to save weight, this limited oil capacity drives the oil temps even higher. Also the oil tanks are made from plastic which I believe does not shed heat as well as a metal tank. A cooler might should be on your shopping list to help cool the motor and oil and the lower temps will make the motor happier. So using 20-50W oil without a cooler and with a limited oil capacity in temps over 70 degrees is not doing your motor any good.

It's not typically a blow-by condition at the rings that will cause excessive oil to be expelled through the breather passages in a tube frame Buell, it's the limited capacity of the oil bag to hold oil whose volume has increased because of aeration by the scavenging pump. The excess volume has no where to go but through the vent line from the oil bag to the cam chest, where it eventually makes its way to the vents in the heads. You can see how the oil is aerated when you check the oil bag level after a hard run at speed. I imagine whatever volume left in the bag must be a dense oil mist. I think one of the reasons for the XBRR style dual stage oil pumps on current XB engines was to address this issue.

The way to avoid blowing oil is to run the oil level lower than the marks on the dipstick indicate. I run my oil level where it just touches the bottom of the dipstick (below the minimum line, actually) and it made a huge difference in oil consumption and the amount of oil ventilated through the heads. To make up for the reduced oil capacity in the oil bag, I run the longer Dyna filter on my 2000 M2. The overall oil capacity is still higher than stock, but it also means I have to keep a closer eye on the level (too low could be catastrophic) Most of the oil I thought my bike was burning was actually being expelled from the breathers as an emulsion of oil and water (I run a catch can). After experimenting with the oil bag volume, most of the stuff in my catch can is water, with very little oil/water emulsion.

Whether you run the breathers back to the carb (like a stock configuration) or to a catch-can, I suggest anyone with a tube frame Buell try this if they are having excessive venting of oil from the cylinderhead breathers and high oil consumption.

I run a Jag’s oil cooler and the larger Toyota truck filter on my X1s and only fill the oil bag to ware its just touching the stick and I still had blow by until I changed to the XB covers with PVC valves. Now there is only a little water in my catch cans before I changed the covers I would have to empty my catch cans on long rides they would fill completely up. I would carry a quart of oil with me so I could add oil if it got to low. As for the oil tank I’m running an oversized aluminum tank on my 2000 x1 and it still did it until the cover change.