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My Big Sucker 2 has never done that and I have had it since 2010. I have since shaved the ears off it, plugged the holes, and run DK Customs breather bolts in the heads to vent to atmosphere and still no issues with oil spewing. Look at this post I made back in 2015 of when I modified my Big Sucker 2 for venting to atmosphere. https://www.hdforums.com/forum/dyna-...ght=big+sucker
Pull your rocker covers and inspect the internal breathers.
my hats what I'm doing on my lrs. I'm gonna drill and tap the stock heavy breather a/c and run the hoses to a splice running into the catch can, then just put a filter on the catch can outlet.
I did that to a Ness, a ventilator and to a few heavy breathers:
OP, by breathers in the context of my post I mean the internal crankcase breather valves in your motor. It seemed from your description that there was a lot of oil, so it's possible you have a bad breather valve.
Thanks for the Clarification. If I'm understanding you correctly you're suggesting that I remove my rocker boxes and check the little rubber seals, and filter in the breathers to make sure they aren't damaged or worn out? My bike is only a year old and only has 12k miles on it, do you think this could be a an issue this early in the bikes life? It was operating just fine before I installed the A.N. AC, I believe you mentioned the stock AC was probably just better as sending the oil back into the intake, but it's such a significant difference my first reaction is to suspect the AC. thank you for all the info
Last edited by sdrawkcabssa; Aug 9, 2017 at 04:53 PM.
I have the big sucker on my bike. I replaced the breather bolts that came with the big sucker with 1 3/4" kuryakyn breather bolts and ran hoses to vent into a catch can. Here is the link for the bolts on Amazon and some pics.
This looks like the easiest and quickest way to try and solve the problem, besides just buying a new AC. I may just do this, thanks. Should I use a catch, or a filter? or both? What size/type of hose did you use?
Last edited by sdrawkcabssa; Aug 9, 2017 at 05:10 PM.
If you got an Arlen Ness Big Sucker for 150 bones, that was the hella deal of the decade
Some Twin Cams are pukers, it's what they do.
Vent that nasty crap to atmosphere, you're doing your intake and engine no favors putting that hot oily gas back in to the intake.
With some bikes, oil level on the stick on a cold check won't get it done. The nature of the beast. You pull the rockers and open the oil drain holes in the plates, add Trask Mystfree breathers, or live with it.
But vent those crankcase gasses to atmosphere, what ever you decide to do...
lol I actually don't remember exactly what I paid for it, just ordered from revzilla, so whatever they have it listed at. Before I had this issue I was already looking to vent to atmosphere because it seemed like such a bad idea to have all that crap going back into my engine, and didn't even know that was originally happening until i did some research.
Thanks for the info, I'm hoping to solve this issue without pulling the rocker boxes but if i have to I will... IF i decide to run hoses, would a catch or a filter be better? Seems like a filter would just perpetuate the same issue in a different area, and wouldn't want to vent it to a dangerous area, say in front of my rear tire... so maybe a catch? Thanks
lol I actually don't remember exactly what I paid for it, just ordered from revzilla, so whatever they have it listed at. Before I had this issue I was already looking to vent to atmosphere because it seemed like such a bad idea to have all that crap going back into my engine, and didn't even know that was originally happening until i did some research.
Thanks for the info, I'm hoping to solve this issue without pulling the rocker boxes but if i have to I will... IF i decide to run hoses, would a catch or a filter be better? Seems like a filter would just perpetuate the same issue in a different area, and wouldn't want to vent it to a dangerous area, say in front of my rear tire... so maybe a catch? Thanks
Yea, venting that hot, oxygen depleted, oily crankcase gasses back in to your throttle body and intake only makes the EPA happy. Your engine hates it
My '13 was something of a puker; oil level could be perfect half way up on the stick on a cold check and she'd still puke oil. I've modded my external breathers at least a half dozen times looking for the right combination of aesthetics and effectiveness.
When I pulled my rocker covers to install the Rock Out rocker inserts I pulled the plates and enlarged the drain holes and that helped a great deal. I did buy Trask Mystfree breathers but enlarging the drain holes and using my current setup is now a zero mess proposition. I will install the Trask's when I pull the heads for upgrades, though
I found an under A/C filter to be the most effective solution; the catch can idea is good as well, but Mchad did report the catch can wasn't as effective as the filters.
I picked up a spare dual inlet filter and just change them out whenever the filter begins to darken. I clean the filter with K&N air filter cleaner, rinse with hot water and it's ready to go again...
Thanks for the feed back, info, experience, links, etc gents. Here's a pick of my dipstick after a quick 40 min ride after work. Didn't puke all over, but there was light spray on the battery box, and drips forming under the AC filter.
