Cobra Catch Can Maybe?

[JTJersey]

I’ll try to be concise here,there is a question and pictures . I’ve been following the crankcase breather venting into the engine topic that’s discussed in thousands of places on the Web. General consensus seems to lean towards the “if you don’t put on a bypass with a catch can your motor will be toast in 10,000 miles.” Usually followed closely by a recommendation of their favorite setup. Not arguing one way or the other and I’ve seen the multiple pictures of crap encrusted pistons from TwinCams. Looked exactly like the crap encrusted pistons on my ‘78 Shovelhead Lowrider that vented to my chain. (Way it came, very handy chain oilier, thought it was a feature.) Rode the ‘78 Shovel for 33 years and would on occasion pull the heads off and clean the crap off the pistons. Unlikely I’ll be riding my ‘21 M8 Freewheeler for 33 years unless I live to 103.

Bear with me. At 2500 miles I replaced the stock HD air box with a Cobra PowerFlo Intake holding a K&N filter. I really liked the look of the HD box, just too big for me and I wanted a K&N filter, but wanted to keep the overall look of the box.



I kept the crankcase breather hose in the factory position. Went to the 5000 mile service that way. At around 6000 miles I was curious if they had “cleaned” my K&N Air Filter and took the cover off. It was practically spotless inside. OK. Since then I would occasionally see an oily film on the back of my air cleaner cover. I’d wipe it off and go about my business. This afternoon I decided to take the entire air cleaner unit apart. I’m at 9000 miles so let’s see. I left the two pics in question full size for examination.



On the vent hose you can clearly see a large drip of oil & moisture content. It hung there ‘till I wiped it off. Below the hose you can see where the oil is dripping on the intake, running down past the screw and dripping from the bottom of the mounting plate into the rubber bottom seal of the K&N filter. There is little or no oil in the filter pleats themselves. Lastly, you’ll see the drip line and collection of oil inside the bottom of the cover. This explaining the eventual film on the outside bottom and rear of the cover that I’ve been wiping off. Here’s the kicker. The inside walls of the intake and the butterfly had almost NO residue on them. Now I know a throttle intake isn’t a Kirby vacuum cleaner suction, but the lack of excessive residue seems to me like this particular Cobra PowerFlo Intake is acting like a rather large catch can? Maybe? Thoughts?

[W3JNP]

Any chance you have to much oil? I've seen several twin cams that will do that when they are overfull.

[Jack Klarich]

Your throttle plate looks pretty dirty, you can bet even tho you do not see oil in the intake, your engine is sucking some of it in, nature of the beast

Something else to consider, as you already know from riding Trouble heads, you will eventually get some oil past valve guides and maybe some past the rings

Once again, nature of the beast

I route my head breathers to a catch can, I dump it when I remember, it has never been much, more water than oil so far

Good pictures and write up JT

[Old Road Dog]

Both my Twincam and M8 have breather bypass's. On the M8 trike I connected hose's to the breather bolts then to a tee then a single hose out the back of the air cleaner routed down between the tranny under the frame to an automotive catch can zip tied to the brake cable mount on left hand side. My Shovelhead has an entirely different breather system no longer EPA approved.

[JTJersey]

Any chance you have to much oil? I've seen several twin cams that will do that when they are overfull.

The dealer did the 5000 mile service. Hoping they know what they're doing Couple of days ago I was down 1 qt checking while good and hot. According to the dip stick I could still go a tad more. This appears to be an accumulation over 4000 miles.

[JTJersey]

Your throttle plate looks pretty dirty, you can bet even tho you do not see oil in the intake, your engine is sucking some of it in, nature of the beast

Something else to consider, as you already know from riding Trouble heads, you will eventually get some oil past valve guides and maybe some past the rings

Once again, nature of the beast I route my head breathers to a catch can, I dump it when I remember, it has never been much, more water than oil so far Good pictures and write up JT

In actuality it really wasn't. 90% of the oil was collecting away from the intake. It may not be a 100% fix, but without violating warranty it seems to be a whole lot better. Could be why Cobra claims a 2-5% power increase over stock. Much the same as that with a catch can installed. I'll check it down the road at 10000 miles and post back.

[Old Road Dog]

Im thinking most of the snot is being sucked into the motor.It needs to be completely routed away from the intake.

[JTJersey]

Im thinking most of the snot is being sucked into the motor.It needs to be completely routed away from the intake.

I'm sure some is still being sucked into the motor, but by the looks of that rather sizeable oil collection that ISN'T being sucked into the motor, that's a lot of oil NOT infiltrating the engine, you have to admit?

[Jack Klarich]

I'm sure some is still being sucked into the motor, but by the looks of that rather sizeable oil collection that ISN'T being sucked into the motor, that's a lot of oil NOT infiltrating the engine, you have to admit?

JT, approx how many miles since you last looked inside the AC cover?

How much oil between oil changes if any ?

[JTJersey]

JT, approx how many miles since you last looked inside the AC cover? How much oil between oil changes if any ?

About 3000 miles since I last looked inside the cover. Put 1 qt in a couple days ago.

[JTJersey]

Here's a thought. EPA regs say you can't vent the crankcase oil into the atmosphere, so most motorcycle, car, etc manufacturers took the easiest most discreet route by venting to the intake. Why would HD or the EPA care if you were venting into a collector can and then disposing of it later? Results the same isn't it? Probably better because your exhaust emissions would be cleaner. Dripping it directly onto the road and into the air would be the no-no they want to avoid. This system has resulted in the center line at intersections and stop streets being a lot cleaner and safer these days, especially for two wheelers.

[Old Road Dog]

There are 3 things whose minds Ive stopped attempting to figure out a long time ago: any Government bureaucrat, HD engineers, and Women.

[Jack Klarich]

Here's a thought. EPA regs say you can't vent the crankcase oil into the atmosphere, so most motorcycle, car, etc manufacturers took the easiest most discreet route by venting to the intake. Why would HD or the EPA care if you were venting into a collector can and then disposing of it later? Results the same isn't it? Probably better because your exhaust emissions would be cleaner. Dripping it directly onto the road and into the air would be the no-no they want to avoid. This system has resulted in the center line at intersections and stop streets being a lot cleaner and safer these days, especially for two wheelers.

I agree 100% and do use a catch can, I have since the Evo engines

The EPA would probably still frown on this as being a work around

I do not care, I can change back in about 5 minutes even on the road if I had to take mine in for a problem @ a dealer

The hot oxygen depleted oily mess is not good for any engine as you already know, you could probably pretty easily fashion a hose and catch can to your IMO handsome Air Cleaner, even if it meant running a bit longer hose to route the catch can out of sight

On my 15 Freewheeler I ran a longer hose back and under the trike with a plastic spigot for a drain

I could open the spigot , drain the oily / water crap out and dispose of it properly

[JTJersey]

One thing for certain is that anybody who sees those pics of my air cleaner can't say the issue doesn't exist. They can choose to ignore if they want, but it does exist.

[rhino 2]

Here's a thought. EPA regs say you can't vent the crankcase oil into the atmosphere, so most motorcycle, car, etc manufacturers took the easiest most discreet route by venting to the intake. Why would HD or the EPA care if you were venting into a collector can and then disposing of it later? Results the same isn't it? Probably better because your exhaust emissions would be cleaner. Dripping it directly onto the road and into the air would be the no-no they want to avoid. This system has resulted in the center line at intersections and stop streets being a lot cleaner and safer these days, especially for two wheelers.

I remember riding to work through the Lincoln tunnel on my two wheeler in the 70’s..It was like riding on Goose sh*t….And stopping at the toll booth was always an adventure..

But getting back to the collector can how many people will empty it in a timely fashion or only after it drips on the road ..Or on their chrome..?

[Jack Klarich]

I remember riding to work through the Lincoln tunnel on my two wheeler in the 70’s..It was like riding on Goose sh*t….And stopping at the toll booth was always an adventure..

But getting back to the collector can how many people will empty it in a timely fashion or only after it drips on the road ..Or on their chrome..?

These folks should not be riding if they don't take reasonable care of their machine IMO

[pigfoot63]

I agree 100% and do use a catch can, I have since the Evo engines

The EPA would probably still frown on this as being a work around

I do not care, I can change back in about 5 minutes even on the road if I had to take mine in for a problem @ a dealer

The hot oxygen depleted oily mess is not good for any engine as you already know, you could probably pretty easily fashion a hose and catch can to your IMO handsome Air Cleaner, even if it meant running a bit longer hose to route the catch can out of sight

On my 15 Freewheeler I ran a longer hose back and under the trike with a plastic spigot for a drain

I could open the spigot , drain the oily / water crap out and dispose of it properly

You got my wheels turning on the breather install, went down to my shop and took a look

this morning. It looks like a very simple install with no hacking and simple enough to put it back

stock even on the side of the road.

[Jack Klarich]

You got my wheels turning on the breather install, went down to my shop and took a look

this morning. It looks like a very simple install with no hacking and simple enough to put it back

stock even on the side of the road.

Here is about as cheap and simple as u can get

[pigfoot63]

Here is about as cheap and simple as u can get

Thanks for this easy fix.

[JTJersey]

Thanks for this easy fix.

That's awesome. Great fix and can't get anymore discreet than that. Looks like a trip to Lowes today for vacuum tube and connector. Question though, as well as being a place for the oil mist to collect shouldn't the container be vented to allow breather venting? Seems like otherwise it may be the same as plugging up the holes in the heads.