HD Original Air Filter On 07 Softail ST

[Jeff Klarich]

Here Ya go.

I have up-graded the Air Cleaner on my '12 Ultra Classic to the SE high-flow one (see pix below). This kit includes the mounting bolts shown in the first set of photos below that are hollow with a port in the side that vents the crankcase to the air cleaner and engine cylinder intake through ports in the back plate. This allows the oily mist from the crankcase to be sucked into the cylinders and "burned". But I do not like this for a couple of reasons:

1. The oily crankcase vapor accumulates in the air filter area and eventually drips out of the A/C cover onto the engine making a mess
2. Burning the oily mist in the engine contributes to carbon buildup and fouling of the IAC over time

So I decided to replace these mounting bolts with the OEM ones from the original backing plate that look like the second set of photos below. Those are also hollow, but they do not have a port in the side of the bolt but rather have a nipple on the end of the bolt (see pix). So I used some fuel hose from the auto parts store and routed that out from behind the cover and down between the engine and the tranny on the right side below the engine about 3 inches (see last 3 pix below). So any venting of the crankcase now blows down below the bike.

Cheers,

TQ

Last edited: Sep 12, 2017
Please stop by the "The Self-Help pages."

 

[Jeff Klarich]

Your backing plate may look different but the same method will apply. As Russ said, many of us have done this conversion and in my opinion makes a huge difference on the junk re entering the engine and extending the life of the air filter.

 

[Tripp]

O my that's nasty.
A lot of us do a bypass on the breather tubes and out to a collection unit or as I have done just to the road. There are some posted pics a while back. Someone should remember where.

Never thought about bypassing the breather tubes... Great idea and I found a great tutorial on YouTube of a dude that did this on his 06 Softail.! Here's the link if anyone wants to check it out

 

[ThunderRogue]

Yes lots of guys go from the Internal Breather stock setup to External Breathers. Either venting to the atmosphere or a catch can. There's the concept that your engine will run better and cooler since you're no longer running hot spent gasses back through your intake. Lots of options out there. You can search any supplier (like JP Cycles) and just enter "external breathers". If you have excess oil accumulated in your filter it's a good option. Some are very inexpensive.

 

[gator508]

Your backing plate may look different but the same method will apply. As Russ said, many of us have done this conversion and in my opinion makes a huge difference on the junk re entering the engine and extending the life of the air filter.

Good job Jeff, knew you would nail it

 

[gator508]

Yes lots of guys go from the Internal Breather stock setup to External Breathers. Either venting to the atmosphere or a catch can. There's the concept that your engine will run better and cooler since you're no longer running hot spent gasses back through your intake. Lots of options out there. You can search any supplier (like JP Cycles) and just enter "external breathers". If you have excess oil accumulated in your filter it's a good option. Some are very inexpensive.

Yea just not legal in some states if you have inspections