Hey guys. I put a longer post/reply together last night with some pictures. It says the post needs to be approved by a moderator, so I am waiting on that. If it's not up this weekend I will try to repost. Thanks for all your help and insight!

 

Do you have oem HD evo rocker boxes or are they S&S? If they are oem, have you replaced the umbrella valves? They do tend to get hard and not work. Or if your having too much crank case pressure maybe you should do a leak down test on the cylinders and rings. You could have too much leakage with out having a oil consumption issue..

 

Not sure why this post didn't make it the first time, but here it is:

@pwmorris the motor is being vented through the stock 1989 crankcase. I am considering adding head breathing in addition, if I can't find a root cause to the leak. From what I can tell I have the correct gaskets for the S&S heads, but I am not sure if it would be easy to tell the difference? If I didn't have the right gaskets would their be oil passages blocked off or would it just be a matter of not correctly sealing the mating surfaces? My understanding was that early and late Evo heads and rockers were interchangeable, is this correct?

I don't notice excessive blow by. The tip of my thunderhead is a little sooty and the exhaust is slightly smoky on startup, but nothing that has struck me as out of the ordinary. I have attached an image of my exhaust valves also, seem pretty clean, but I am no expert and have to admit I'm not exactly sure what healthy valves look like compared to problem ones.

Without getting the rockers resurfaced or inspected, they sure seemed to be flat. I unfortunately don't have a picture of them apart, but I have attached an image of what they look like installed (though I doubt it will help this conversation).

The hardware used was correct and torqued to spec to the best of my ability. I was fairly diligent during installation, but I will pay extra attention the next go around as well.

I 100% agree that the setup could have compounding problems (HD jugs, S&S heads, Boyd boxes), but since the problem was present prior to the roxers I think there could be something else going on...

I am going to dig into the motor in the next week or two, but am just waiting to gather as much knowledge as I can prior to doing the work (since I've done 'this' three times already with no luck).

Again, thank you guys very much for the insight and help, the combined knowledge and experience on this forum is invaluable to a guy like me.

 

 

It's been so long since I had stock EVO heads I don't remember if the gaskets are identical to the S&S ones. I would think the EVO set ups would be the same- maybe someone will chime in.
Evo engines use a pair of umbrella valves located inside the rocker boxes-as said they could be old.
The umbrella valves should be in the middle rocker box cover right above the breather holes in the head. Just take of the top rocker box covers and you should see them. There is just one valve per cylinder. Another rocker box issue-Looked up those Boyd's boxes but couldn't find much on them. Confirm they have umbrella valves, or can you take off the cover and take a couple pictures?
I vent my S&S heads, both when I had an EVO, and now twin cam, so that would be my next move-crankcase vent and head vents. Just to the right off your picture is the head breather bolts-are they both sealed shut? If not, you could run lines from them to a "T" and vent to a catch can, which is then vented to atmosphere, or use gravity and put a filter on the end and zip tie it under the tank.

Unfortunately, could be excessive blow by due to worn rings but don't know if you can do a leakdown test.



https://www.hdforums.com/forum/evo-c...-breather.html

Finally, is it possible you have too much oil in the bike? Drain case, and see how much oil in there-this will also be a check for sumping.
I run my oil in my bikes 1 quart low.

 

Thanks for all the input PWMORRIS. I installed the Boyd boxes and can confirm they have the umbrella valves installed correctly. They appeared to be in good shape and weren't hardened, but may be another thing worth replacing upon rebuild.

The air cleaner head bolts are solid currently, but I am going to add head breathing to see if that helps alleviate the problem.

At this point I think my plan will be to:
1) rebuild the top end so that I can check piston/ring wear, replace all gaskets (using a small amount of the aviation gasket sealer), and re-torque all bolts.
2) add head breathing
3) change oil and refill slightly low to ensure I don't have too much in there currently

Hoping to complete the rebuild in the next week or two so I will update when information becomes available.

As always, I appreciate the help and feel free to chime in if anyone thinks we are missing something.

 

Sounds good-
Make sure your oil system is completely drained before refill. Drain case (like I said, check for stumping) completely, lines, and filter. Then refill with a slightly lower oil level.
Your plan sounds solid (fresh rings) and I'm guessing should take care of your issue. Make sure you torque the bolts in the proper torque sequence, as well as a correct break in of those rings.

 

There is more than you think to converting a case breather to a head breather.

You will need to also change the cam cover to a late model unit, but that later model cam cover is designed to be used with a longer pinion shaft...

If you had enough pressure in the breather to blow out gaskets on the rockers, it would be puking oil out the breather.

You need to get the rocker boxes and the heads onto a surface plate and make sure the sealing surfaces are flat.

There is no need for butterfly valves in your rocker boxes, in your breather configuration they do not have a function.

 

Curious if you currently run S&S EVO or twin cam heads or use Boyd's boxes?

Are you saying his constant leaking head and rocker box issues are due to non flat rocker boxes?
No way to tell on the internet but I assumed he checked that already. Like I said, I have never used Boyd's boxes.

As far as pressure blowing out the case breather if there was pressure and oil accumulation upstairs, before I ran head breathers, I was blowing oil out the pipe after hi rpm long rides, but didn't blow out anything thru my case breather. After the heads were allowed to breath, problem solved.
With OP's S&S heads he, as I did with mine, can drill and tap both heads to run head breathers to a "T" with a one way check valve to a gravity fed filter or to a catch can with atmospheric vent. Also run the case vent. Done.
I have run this set up with both EVO and twin cam S&S heads and it works well.

My twin cam street bike currently with S&S heads runs a oil tank breather with one way check valve, case breather to atmosphere, and both heads vented with one way check valve with all going to a catch can which is then vented to atmosphere.
Great ring seal, oil pressure, no leaks, puking or any issues with hi rpm as long as I want...

 

This might help the OP with his S&S EVO heads-

From S&S and the differences between their EVO and TC heads-

S&S SSW+ engines are similar to Evolution style engines, but when it comes to the way they handle crankcase venting, they are a whole 'nother animal! Most S&S Evolution style and SSW+ engines have two engine breathing systems that can be used separately, or together, commonly referred to as case breathing, and head breathing.

For case breathing, SSW+ engines still uses the venerable breather gear to regulate the engine's internal airflow, just like the Evolution style engines before it. However, the head breathing arrangement is markedly different. SSW+ engines don't use hollow breather bolts to vent excess crankcase pressure to the outside. Instead, the head breathing arrangement of a SSW+ engine consists of two hoses—a small hose on the front head, and a larger hose, equipped with a one-way check valve on the rear head. (More on the check valve in a minute).

The front hose is routed from the front head to the intake manifold. It applies manifold vacuum to the crankcase anytime the engine is running. The rear hose is routed from the rear head to the carburetor backing plate (or other suitable location). Its purpose is to relieve excess crankcase pressure at all RPMs. Unlike the hose on the front head, the hose on the rear head doesn't do anything until pressure builds in the crankcase. Just remember, the front hose sucks, the rear hose blows.

The rear head breather hose on an SSW+ engine performs the same function as the breather bolts on an Evo engine; that is, venting excess crankcase pressure to the outside, without allowing outside air back in. Both engines use a check valve to perform this function.

Evo engines use a pair of umbrella valves located inside the rocker boxes, while SSW+ engines use a one-way check valve, S&S Part #50-8122. It is located outside the engine, placed in the aforementioned rear head breather hose. The one way check valve must be used with the rear head breather hose, no exceptions. (By the way, SSW+ rocker boxes will have provision for Evo style venting, but it is not functional).