Why you need an external breather...Real world

[DOKK]

This is why I usually run a filter in the winter. This is condensation from a weeks worth of rides to work (15 miles each way) and one longer ride today. There is more water than oil but otherwise this would go right back into my intake and cylinders. And yes, I get it up to temp on my rides to work but I believe this comes from startup and after shutdown.

This also doesn't count what was in the sponges in the catch can.

 

[Jack Klarich]

Expect to see more condensation on cooler mornings, I found this to be true for me here in Florida

You are right to have that nasty water/ oily mess going into your engine, this is always my first mod to all of my bikes/ trikes

 

[DK Custom Products]

Yep, colder weather makes the mix higher in condensed water. Thanks for posting the photo, glad your Catch-Can is keeping it out of your engine internals.

Cold weather mix-

Warm weather mix-

Kevin

 

[Be Smooth]

First Upgrade I made

I made my first post introducing myself six months ago when I ordered my Freewheeler. This is my first M8. The only experience I’ve ever had was with EVO’s. I put 190 miles on my trike and bought a DK customs 686V and a catch can. After watching tons of videos, and getting an understanding of how these things work, I truly did feel this was the very first mod that needed to be made as quick as I could.

 

[Notgrownup]

Not in a huge rush to put it on because I’m not riding a lot right now because of the cold but I have all stuff to build mine.

 

[Dan SC]

The condensation in the catch can is not moisture that came from the engine.

It is condensation from the outside air.

We really should call them "Condensation Cans", because that is what they are...

When the engine shuts down the can cools off, and moisture from the atmosphere condenses in the can.

If you run a hose that is open at the end, you won`t see any condensation drops on the hose or underneath the machine.

I have been running open end breather hoses on my machines for 34 years without issue.

You don`t need any filter or can on the end of the breather hose.

My M8 breather setup.

 

[Jack Klarich]

The condensation in the catch can is not moisture that came from the engine.

It is condensation from the outside air.

We really should call them "Condensation Cans", because that is what they are...

When the engine shuts down the can cools off, and moisture from the atmosphere condenses in the can.

If you run a hose that is open at the end, you won`t see any condensation drops on the hose or underneath the machine.

I have been running open end breather hoses on my machines for 34 years without issue.

You don`t need any filter or can on the end of the breather hose.

My M8 breather setup.

View attachment 116429

Partly right, the byproduct of an ICE is water vapor and carbon dioxide, when it cools leaving the combustion chamber via the exhaust it condenses

 

[Dan SC]

Partly right, the byproduct of an ICE is water vapor and carbon dioxide, when it cools leaving the combustion chamber via the exhaust it condenses

We are not talking about the moisture in the exhaust, we are talking about the breather air, which is the air below the pistons...

The breather air and the catch can have nothing to do with the air coming out of the combustion chamber...

My explanation was not "Partly Right", it was accurate.

The water in the catch can is not from the engine, it is from the outside atmosphere, and it condenses on the inside surfaces of the can.

Forget about spending money on a catch can, just route the breather hose down away from the rear wheel, and you will see no moisture buildup on the end of the hose.

 

[Old Road Dog]

We are not talking about the moisture in the exhaust, we are talking about the breather air, which is the air below the pistons...

The breather air and the catch can have nothing to do with the air coming out of the combustion chamber...

My explanation was not "Partly Right", it was accurate.

The water in the catch can is not from the engine, it is from the outside atmosphere, and it condenses on the inside surfaces of the can.

Forget about spending money on a catch can, just route the breather hose down away from the rear wheel, and you will see no moisture buildup on the end of the hose.

RUBBISH! How do you account for the fact that my catch can is mounted on the LHS brake cable mount above the axle with a hose running all the back to the air cleaner and theres moisture snot in the can? Is that due to engine heat? Just because you dont see it dosnt make it true.

 

[Rogue1]

We are not talking about the moisture in the exhaust, we are talking about the breather air, which is the air below the pistons...

The breather air and the catch can have nothing to do with the air coming out of the combustion chamber...

My explanation was not "Partly Right", it was accurate.

The water in the catch can is not from the engine, it is from the outside atmosphere, and it condenses on the inside surfaces of the can.

Forget about spending money on a catch can, just route the breather hose down away from the rear wheel, and you will see no moisture buildup on the end of the hose.

Correct me if I'm wrong but are you saying that moisture does not condensate on the inside of the engine cases?. I don't understand why it would condensate on the inside of the catch can but not the inside of the engine cases. I am only an American Motorcycle Institute graduate and not a Professional Mechanic as you say you are, working on motorcycles for more than 50 years I have seen the condensation especially in bikes that sit for a long time.

 

[Dan SC]

Correct me if I'm wrong but are you saying that moisture does not condensate on the inside of the engine cases?.

Did I say that?

Read my post again and tell me where I said there is no condensation inside the engine...

Of course there is moisture...Inside any machine that heats up and cools down.

My post was about moisture that condenses in breather catch cans.

 

[Rogue1]

So what happens to the condensation that is inside the motor?

 

[Jack Klarich]

So what happens to the condensation that is inside the motor?

Once the engine oil is up to operating temperature the vapor starts to burn off, this is one of 2 reasons Harley owners manuals worded to change your oil more often when short rides in lower air temperatures

Oil breaks down faster( more acids built up in oil) and in below freezing weather ice sludge would develop causing bad JU JU to internal oil galleries

 

[14TG]

Over the past 7 years or so, I always ran an external breather because the amount of oil that was on my air filters was concerning.

I definitely do NOT want that oil getting into the throttle body and attempting to re-burn. I’m in Pennsylvania and all the bikes I’ve owned (and now the Tri glide) are “recreational” and ridden spring thru Fall, so I will ALWAYS have external breathers on all my bikes.

I highly recommend them & DK has some great kits!

(Last pic showing the filter keeps loading sideways… but the pics show my set up).

I have a few spare filters and clean them every 3-5k miles.

 

[UNWOKE]

Any thoughts on my setup? It’s a DK catch-can temporarily mounted in the air box, just wedged in for now. It seems to work as intended but I haven’t seen it done before so I was wondering why and if I should redo it. Thanks

 

[rhino 2]

Any thoughts on my setup? It’s a DK catch-can temporarily mounted in the air box, just wedged in for now. It seems to work as intended but I haven’t seen it done before so I was wondering why and if I should redo it. Thanks

Donald.......Welcome to Trike Talk......What trike is it mounted on?.....Your profile says you are looking??..

 

[Jack Klarich]

Any thoughts on my setup? It’s a DK catch-can temporarily mounted in the air box, just wedged in for now. It seems to work as intended but I haven’t seen it done before so I was wondering why and if I should redo it. Thanks

Hi Donald, Welcome to Trike Talk and your first post

Yes You can run the catch can as is, but it does mess up the air flow in the air box

You can drill a hole in the bottom of the air box to run the hose out and attach your catch can

 

[RKplus10]

Welcome to TrikeTalk, Donald! You’re catching all the snot but my thinking is that the nasty vapors are still being sucked into the throttle body. Also, that fancy catch can is too purdy to hide.

 

[nucseal]

Any thoughts on my setup? It’s a DK catch-can temporarily mounted in the air box, just wedged in for now. It seems to work as intended but I haven’t seen it done before so I was wondering why and if I should redo it. Thanks

There is multiple pictures in this thread, how should be run. Definitely, the catch can needs to be outside the air box, so oil vapor does not reach the engine.

 

[UNWOKE]

Hey all, thanks for the welcomes. I have it on a new 2023 Tri Glide with 8 miles on it so my thoughts were to leave it in the air box until I figure out the routing and mounting. I hadn’t thought of the vapors just assumed the air filter would clean most of that up and I’d change the filter more often. Now I understand why I haven’t seen it mounted as such before, thanks for the education.