Oil in the Intake after Venting Externally

[FloridaJim5]

Just wanted to get an opinion on the oil I found in the intake manifold when installing a new SE Aluminum intake a couple of days ago.   

It's a 2019 Ultra with a 107 with only slip on mufflers and a little less than 10,000 miles.  The pic below is about 1,000 miles after venting the breathers externally open to the atmosphere - no catch can.  When installing the external breather, I didn't remove the throttle body and I only cleaned the outside of the  throttle blade and just what I could wipe out reaching through the while holding the blade open. 

When installing the SE intake, I expected to see a clean intake manifold.  Could the oil in the pic be left over from before I installed the breather?  Maybe I couldn't reach far enough in thru the throttle body to clean out the intake I'm assuming?  Or does this indicate another problem?   

I will say that the intake valves are clean as I could get a good view with the intake taken off before installing the new SE part. 

[Hossamania]

Post a pic of your external breather set up.
That could be caused by some reversion in the system, a combo of fuel and residual oil.
Are you lugging the motor?
Clean it up and check it again after a couple hundred miles.
Which air filter are you running?

[FloridaJim5]

I'm externally venting the stock air cleaner/filter.  The hoses are high-temp silicone and routed between the cylinders and down between the engine and primary.  I checked the flow of the hoses when installing the SE intake manifold a couple of days ago and they flow freely.   

I'm not a lugger and like to cruise at 3,000 rpm's.  I'm not really concerned about the oil and I believe it's just residual from when it had the stock breathers dumping into the throttle body.  Just wanted an opinion. 

[Hossamania]

Looks good, clean it up, keep an eye on it.

[FXDBI]

Any oil usage between changes? What do the plugs look like? Got a borescope check the pistons for carbon. With the hoses run to ground the only other source I can think of would be valve seals    I would ride it and just keep a eye on it if it was mine for now and clean it when you change oil.   Bob

[Jim Bronson]

Interesting timing for your post That is too much oil puddling in the intake. Something is afoot. I took mine apart yesterday, about 700 mi after installing a catch can. I won't be re-installing the can because I'm not happy with the way it is spitting air/oil on my pipes and right side of the engine. Instead, I rerouted the hose to drain to the ground at the rear of the engine. I was pleasantly shocked to see not a trace of oil in the intake even when wiping with a clean rag. I agree to just ride it for a while and take another look.

[FloridaJim5]

Any oil usage between changes? What do the plugs look like? Got a borescope check the pistons for carbon. With the hoses run to ground the only other source I can think of would be valve seals    I would ride it and just keep a eye on it if it was mine for now and clean it when you change oil.  Bob

No oil usage and I just changed the plugs.  They are very clean; almost too clean.  As I was changing the intake manifold to the SE intake, I could get a good view of the intake valves.  They were also very clean, so I'm thinking the pistons are clean as well.  I may buy a borescope just to take a look. 

The only thing I can imagine at this point is that this oil was puddled in the intake before I ran the vent to atmosphere and it just stayed puddled there. When I cleaned the throttle body at the time of installing the external vents, I couldn't reach much past the throttle blade with my finger and a shop towel.  Just surprised me that there was oil puddled in there when I removed the throttle body a couple of days ago. 

Hoss:  I'll keep an eye on it. 

[FloridaJim5]

Interesting timing for your post That is too much oil puddling in the intake. Something is afoot. I took mine apart yesterday, about 700 mi after installing a catch can. I won't be re-installing the can because I'm not happy with the way it is spitting air/oil on my pipes and right side of the engine. Instead, I rerouted the hose to drain to the ground at the rear of the engine. I was pleasantly shocked to see not a trace of oil in the intake even when wiping with a clean rag. I agree to just ride it for a while and take another look.

That is also what I found with the external breather I installed.  Not one single drop of oil out of the breather hoses on my garage floor.  I find that very interesting too and I forgot to mention it earlier.   

[louloupa]

Interesting timing for your post That is too much oil puddling in the intake. Something is afoot. I took mine apart yesterday, about 700 mi after installing a catch can. I won't be re-installing the can because I'm not happy with the way it is spitting air/oil on my pipes and right side of the engine. Instead, I rerouted the hose to drain to the ground at the rear of the engine. I was pleasantly shocked to see not a trace of oil in the intake even when wiping with a clean rag. I agree to just ride it for a while and take another look.

That is also what I found with the external breather I installed.  Not one single drop of oil out of the breather hoses on my garage floor.  I find that very interesting too and I forgot to mention it earlier.   

which proves that rerouting the breather pipes is useless.
I added ventilation with a check valve to the gearbox cover and with the oil level at half the gauge, I don't have a drop of oil in my TB.

[Deye76]

I wouldn't categorize breathing the heads outside of the intake as "useless".
FloridaJim, if it still is a problem might be excessive crankcase pressure, try a Trask vent, or modify your tans top cover to mimic.
https://traskperformance.com/products/checkm8-vented-transmission-top-cover

[Dan89flstc]

which proves that rerouting the breather pipes is useless.
 

Nonsense

Simply venting the hoses overboard is all that is needed, no catch cans or valves.

The oil in the intake manifold is just residual oil from before the breather was re routed.

[Hossamania]

Interesting timing for your post That is too much oil puddling in the intake. Something is afoot. I took mine apart yesterday, about 700 mi after installing a catch can. I won't be re-installing the can because I'm not happy with the way it is spitting air/oil on my pipes and right side of the engine. Instead, I rerouted the hose to drain to the ground at the rear of the engine. I was pleasantly shocked to see not a trace of oil in the intake even when wiping with a clean rag. I agree to just ride it for a while and take another look.

That is also what I found with the external breather I installed.  Not one single drop of oil out of the breather hoses on my garage floor.  I find that very interesting too and I forgot to mention it earlier.   

which proves that rerouting the breather pipes is useless.
I added ventilation with a check valve to the gearbox cover and with the oil level at half the gauge, I don't have a drop of oil in my TB.

No drops, but my guess is that there is a film of oil coating the tb and intake manifold.

[FloridaJim5]

which proves that rerouting the breather pipes is useless.
 

Nonsense

Simply venting the hoses overboard is all that is needed, no catch cans or valves.

The oil in the intake manifold is just residual oil from before the breather was re routed.

I'm convinced it's residual from before I vented externally.  It was just interesting and a little surprising to see it still there.

[Jim Bronson]

I'm convinced it's residual from before I vented externally.  It was just interesting and a little surprising to see it still there.

Which is why I carefully cleaned my intake before I installed the exernal vent hoses. I was always used to seeing an oil puddle in the bottom of the intake, but it is clean as a pin now. I wonder what the tops of pistons look like after a few thousand miles. Hopefully, my new S&S top end will stay cleaner with the venting.

[rigidthumper]

There will always be some residue on pistons & combustion chambers that accumulates, because the fuel we use is an oil based product. If you have poor ring seal, there will be a cleanish perimeter on the top of the piston, if you have bad valve stem seals, crud on the valve & guides.

[truckrglenn]

Did you clean the air filter? My Harley air filter looked good at a quick glance, but there was still left over oil in it.

[FloridaJim5]

Did you clean the air filter? My Harley air filter looked good at a quick glance, but there was still left over oil in it.

I inspected it inside and out. The filter was clean and oil free.  I'm pretty sure it was left over from before I vented it externally.   

[roadkingdresser]

I don't know if it means anything, but today I took the cover off of my wifes trike to change the plastic intake manifold. The breather bolts that go thru the beather and the bracket that holds the fuel injection system had oil seeping thru the threads and into the back air cleaner plate. When I put it back together I made 2 thin gaskets-one at the head and 1 at the inside of the backing plate.

[FloridaJim5]

I don't know if it means anything, but today I took the cover off of my wifes trike to change the plastic intake manifold. The breather bolts that go thru the beather and the bracket that holds the fuel injection system had oil seeping thru the threads and into the back air cleaner plate. When I put it back together I made 2 thin gaskets-one at the head and 1 at the inside of the backing plate.

Probably just means the threads were not sealed, but if you have oil on the backplate and in the intake, it's coming from the breather tubes.