Motorcycle Oil Catch Cans, The Answer?

It is no secret that I have a problem with oil collecting in my motorcycle air box( Fed Up With Oil In My Motorcycle AirBox ). I’ve been trying to modify my TaoTao TBR7 motorcycle air filter box for better performance and reliability. As time passed, I’ve become increasingly irritated by the amount of oil in my air filter box and wondered if motorcycle catch cans are the answer.

Oil in motorcycle air box.
Oil in air box, will a motorcycle oil catch can prevent this?

I’ve taken steps to minimize oil both reaching my air filter box and to become a problem for my motorcycle engine:

  1. I’ve ensured the TBR7’s motorcycle crankcase oil level is not too high( What Is The TaoTao TBR7’s Oil Capacity? – FAQ ).  
  2. I use the correct type of weight of motorcycle engine oil ( What TBR7 Oil Type Do I Need? )
  3. Also, I’ve upgraded to a motorcycle air pod ( TBR7 Air Filter Pod Replacement ) , meaning no more excess oil leaking into the engine intake, fouling the carburetor, or dripping out onto the engine exhaust—less smoking engine parts.

Even with these steps, a small amount of oil/oil vapor is carried over into the motorcycle air filter housing. Over time, this tiny amount accumulates in the bottom of the air filter box and starts to overflow or is splashed out with motorcycle movement. 

I want a solution, and I believe I found one, a Motorcycle Oil Catch Can.

What Is A Motorcycle Oil Catch Can?

This was my first question when I saw one in person and started reading about them online.

How my airbox filter housing acts as a reservoir of any carried-over motor oil from the crankcase vent, the motorcycle oil catch can act as a regular oil trap instead.

The motorcycle oil catch can is specifically designed to catch, trap, and hold any oil from the engine crankcase vent. Also, a big part of the oil is held without creating a mess till the oil can be adequately drained.

That is it!

What Can A Catch Can Do?

Instead of an air filter housing catching oil and leaking everywhere, someone created a motorcycle add-on device to do the oil catching without making a mess.

How Does An Oil Catch Can Work?

Rather than go into too much technical detail, I found examples of how the oil catch can work.

Know how a shop vac works?

The large items are entrained in the air, and you suck them up into the shop vac. These items fall to the bottom of the canister, smaller items get trapped in the filter(hopefully also falling to the bottom of the canister once the vacuum is off), and the air is exhausted from the shop vac. Well, an oil catch can kind of works like that.

Crankcase exhaust/gasses exit and flow into the catch can, making sharp twists and turns that only the gases can make. The heavier oil particles are directed into the bottom and walls of the can, where they collect in the bottom of the can.  

There is a filter for even finer particles to become trapped; hopefully, when the engine is off, those finer particles fall to the bottom of the can.  

The only thing exiting the oil catch can is crankcase gases.

Is There A Motorcycle Oil Catch Can Breather?

Yes, just like there are crankcase breathers, the oil catch can sit between the crankcase exit and the crankcase breather.

Some oil catch cans have an integrated breather built on top of them, so it’s all one piece.

What Does A Breather Do On A Catch Can?

It vents the catch can.  

The driving force for the crankcase gases is the difference in pressure; the higher pressure inside the crankcase compared to the atmospheric pressure outside the breather.

Can You Vent A Catch Can To Atmosphere?

A vent to the atmosphere is a typical design I see with the aftermarket motorcycle add-ons. The motorcycle oil catch can is directly vented(through a filter) to the atmosphere. 

Can Oil Catch Can Crank Case Gases Be Rerouted?

This is my big question; I might not want to vent the crankcase exhaust gases into the atmosphere, and I want to reroute the oil catch can vent to the carburetor inlet area.  

This way, any unburnt gases get a second chance to burn, and I’m not too fond of the smell of unburnt gasoline.

I don’t have an oil catch can on my TBR7 motorcycle, so I will have to look further into this option.

Where Is This Crankcase Pressure Coming From?

Minute amounts of exhaust gases leaking past the piston rings into the crankcase space. Pressure gradually builds till pressure on both the top and bottom of the piston equalizes, and you can guess the motor stops working.

Pistons move up and down, during the ignition process, due to pressure differences between the top and bottom of the piston. As I explained, once that pressure difference disappears, the piston no longer moves.

Do Oil Catch Cans Increase Crankcase Pressure?

From what I read, this is opposite to the purpose of an oil catch can; it catches carryover oil while allowing for proper venting of any crankcase pressure.

Can A Motorcycle Oil Catch Improve Performance?

An adequately ventilated motorcycle engine crankcase relieves the below piston crankcase pressure and maximizes the differential pressure across the piston.

This condition allows for maximum downward movement of the piston and, hopefully, the complete energy extraction from the gasoline.

It seems to improve performance, not beyond the engine’s design, but maintain performance; sure, it looks like it can do that.

Can An Motorcycle Oil Catch Can Add Horsepower?

Not that I found. The engine is limited by design and how you operate it, so I do not believe it can add horsepower to your engine.

However, I believe it helps maintain the performance of your motorcycle engine due to proper venting of crankcase pressure from the underside of the piston.

Can An Oil Catch Can Damage Your Engine?

Well, I guess anything operated improperly could damage your engine, so the oil catch can should be used properly.

Proper venting, proper draining of oil, proper installation, etc.

Again, I found nothing to suggest a motorcycle oil catch can damage my TBR7 motorcycle, so I am leaning towards getting one installed.

So does an oil catch can cause motorcycle problems? If you know, please leave a comment.

Do I Need A Motorcycle Oil Catch Can?

Why I am writing this post, an oil catch can should be the solution I’ve been looking for. Having oil in my TBR7 motorcycle oil air box is a pain due to the mess it makes. 

Capping the crankcase vent line could cause operational problems for the motorcycle engine, so it must always stay vented.

How Do You Put An Oil Catch Can On A Motorcycle?

If I get an oil catch can for my TBR7 motorcycle, I plan to have it on the right side of the bike near the carburetor.  

The bike’s right side is the same side the current crankcase vent line is routed to the air box, so it seems like a good location.

Where Do You Hook Up An Oil Catch Can?

Once on the right side of my TBR7 motorcycle, I will have the can easily be plumbed between the crankcase vent line and somewhere it can be vented properly. I would like to have it vented or return the crankcase gases to the engine inlet(carb area).

I am also interested in being hooked up so I can quickly drain any excess oil it catches.

Do Motorcycle Oil Catch Cans Get Hot?

I figured having hot motorcycle crankcase exhaust gases flowing through the oil catch can will get warm if not fully hot. 

Possible burn hazards have me considering locations for the oil catch can: inside the motorcycle frame area and away from my leg or other body parts.

Do Cheap Motorcycle Oil Catch Cans Work?

I hope so. I plan on not spending much money on it. I own a TaoTao TBR7 motorcycle; being a Chonda owner, I am known for being cheap ah frugal with my money.

So frugal, sometimes we make stuff ourselves.  

How Do You Make Homemade Oil Catch Cans?

Great idea!

Doing DIY projects with handcrafted items on your TaoTao TBR7 motorcycle is the Chonda-Way!

It looks like a small container with an inlet(from engine crankcase vent) and either a vent(vented to atmosphere) or a return line(to engine intake), with a way to hold and drain oil it catches.  

Sounds easy, right?

I didn’t make an oil catch can for my motorcycle, but I ran a hose high up under the bike’s seat. The inner diameter of the hose holds oil mist, so the longer length allows oil droplets to collect and drain back to the crankcase.

So I did make a Pseudo oil catch can for my motorcycle, but with my design, it is both vented and allows oil to drain back into the motorcycle motor’s crankcase slowly.

If you have a way to make your DIY motorcycle oil catch can, please send me the instructions with completed photos. I am interested in seeing how you made it work.  

Since I’m pretty sure I would have it leaking oil everywhere. So I’ll pass on making my own DIY motorcycle oil catch can for now. 😀

Found Simple Oil Catch Cans Online.

I found several oil catch cans online made for car engines, and I found a simple one with the basic design of an inlet and outlet for crankcase gases and a reservoir for collecting oil mist.

Not Done With The Oil In The Air Box Problem, Yet.

I will look further into a solution for the oil issues and post them here. For now, thinking an oil catch can will help, and hoping someone reading this will leave feedback on their experiences.

I still have Catch Can questions:

  • What hose for oil catch can?
  • Do I need a check valve for the oil catch can?
  • What is the hose that connects to the PCV valve?
  • How often should I drain my oil catch can?
  • Why does my catch can fill up so fast?
  • Is it worth installing a catch can?
  • Are oil catch cans a waste of money?
  • Are oil catch cans a gimmick?
  • Can a catch void warranty?

Thank you,

Ride Safe, Ride Fun!

Click To See My Recommended
TBR7 Upgrades

Picture of me, as a New Motorcyclist.
Just Me…Newly Licensed.

Hi I’m Tom, A New Motorcycle Rider and Blog Author.

I am a new rider(Pa Learners Permit at the end of 2020, and I received a Pa Motorcycle License in 2021 after passing a Motorcycle Safety Course).

I bought my first motorcycle, a TaoTao TBR7, at the beginning of 2021 and have been doing upgrades on that motorcycle since.

I added to my motorcycle collection by buying a Boom Vader Gen 2 in 2022, and that Grom-Clone motorcycle has been upgraded by me as well.

I continue to ride my Boom Vader Gen 2 motorcycle as well as my TaoTao TBR7 dual-sport bike.

Read more on my About Me page.

Fun Fact: I’ve only been on one group ride.

Leave a Comment