Oil Contaminant Separator (OCS) Orientation: The Official Word

[SpudRider]

The CSC Blog just announced the official word on the orientation of the oil contaminant separator (OCS). CSC says the clamp should be at the top, and the hose connected at the bottom, as shown in the link below.

http://californiascooterco.com/blog/?p=21183



CSC is employing the exact same logic we concluded on this forum, but is aiming for a different result. Placing the OCS in the CSC orientation maximizes the amount of fuel collected in the clear tube at the bottom of the OCS. Placing the OCS in the opposite orientation minimizes the amount of fuel collected in the OCS, and sends more atomized fuel to the air box, where it can be burned in the combustion process.

Less than a week ago I received a personal message regarding the OCS orientation from forum member Fritz, in Bavaria, Germany. I hope he doesn't mind if I post part of his message.

I found something related to the fuel in the overflow line. According to the drawing in the documents showing the recirculation system, the orientation of the OCS is actually mounted correctly from the factory assuming the US setup is the same as the European.

Considering the fact that mounting it upside down will reduce the amount of fuel in the line I have an idea why it is still mounted as shown on the drawing.

A gas recycling device is probably compulsory so they added it. But burning this recirculated fuel can actually influence your emissions in a negative way. This is due to the fact that the fuel from crank case can not be considered by the ECU with this system setup (additional valve and carbon canister including a load model would change that) and therefore enriching the mixture in an uncontrolled manner. Which means only the feedback control of the lambda sonde can compensate when it is actually already to late and the lambda value is no longer 1 and the catalyst is not working at its most efficient operation point.

On the other hand I guess there is no regulation limiting the amount of fuel collected in the line since it is assumed that it will be disposed correctly.

Long story short the mount of the factory is correct according to the drawings provided for European type approval including emission testing.

So there you have it. Mounting the OCS as shown in the photograph above is the offical orientation. As we have proven, it will result in more fuel being collected in the clear tube, and less fuel being added to the combustion process. This orientation is probably stipulated by exhaust emissions criteria, more than anything else.

[SpudRider]

My OCS came from the factory with the opposite orientation, as did the initial bikes delivered to CSC, and many others on this forum. I do know the official orientation will definitely collect more fuel in the clear tube below the OCS.

At the 12:32 mark in the following video, you can see the OCS was not installed in the official orientation during the CSC Western States tour.

[AdventureDad]

I dont have mine yet...but I'm wondering for those who take long rides, what happens when the tube gets totally filled and one keeps riding? I'm not saying ignore it, but if someone is doing a long ride out of state or whatever, and the tube gets filled and the rider misses it, what could a negative outcome be?

[Inroads]

Originally Posted by AdventureDad

I dont have mine yet...but I'm wondering for those who take long rides, what happens when the tube gets totally filled and one keeps riding? I'm not saying ignore it, but if someone is doing a long ride out of state or whatever, and the tube gets filled and the rider misses it, what could a negative outcome be?

Mine fills up fast on highway rides and so I have pulled my drain plug about
Half-way out to allow a slow drip out the bottom onto the ground.

[maxhdrm]

Interesting .... when I picked up my bike two weeks ago last Saturday at CSC my OCS valve was mounted in the "official" CSC position. At about 225 miles I did a oil change and drained about 3 inches of liquid from the line. About 60 miles ago I saw the posts about the "up side down" OCS and flipped the valve to the "non-official" position, last night saw the blog entry on the "official" OCS valve position so this afternoon I went to flip it back, notice no liquid in the tube but when I flipped the valve a nice puddle of fuel smelling liquid emptied out of the valve. Was not expecting that after only 60 or so miles! Oh and if you have the upgraded skid plate, it makes getting the OCS bracket off/on a bit more challenging! Glad it is all resolved!

[detours]

Originally Posted by AdventureDad

I dont have mine yet...but I'm wondering for those who take long rides, what happens when the tube gets totally filled and one keeps riding? I'm not saying ignore it, but if someone is doing a long ride out of state or whatever, and the tube gets filled and the rider misses it, what could a negative outcome be?

This has happened to me several times on rides longer than 3-4 hours. I've pulled the tube out from the OCS and liquid drips out of the OCS for a minute.

This means that fuel is starting to fill the OCS and block suction. When that happens, vapors will no longer be drawn from the crankcase and fuel will build up in your oil.

Obviously, you can drain it at every stop ... or pull the plug and let the fuel/oil/water drip to the ground all the time. But I really hate the idea of pouring out even more fuel than I already have to.

Unless I hear a convincing argument (as to why it's better to pour gas on the ground than to burn it), I'm going to stick with the opposite orientation. I've been running it like this for several thousand miles with no ill effects, no loss of power and good mpg (65 to 70 mpg).

And if it makes the engine run slightly richer ... well, I was going to pour that gas out anyway. I might as well give it a chance to burn inside the engine before sending it out the tailpipe.

[Ron B]

im going to stop by home depot on the way home and pick up one of these to replace the plug to make draining easier with out getting gas all over (lawn mower cut off)

[detours]

Originally Posted by SpudRider

So there you have it. Mounting the OCS as shown in the photograph above is the offical orientation. As we have proven, it will result in more fuel being collected in the clear tube, and less fuel being added to the combustion process. This orientation is probably stipulated by exhaust emissions criteria, more than anything else.

I have much to learn about emissions and fuel injection systems. But doesn't the O2 sensor detect O2 in the exhaust and optimize fuel injection to compensate?

In other words, if extra fuel vapor is added from the OCS, wouldn't the fuel injection system reduce fuel for an optimal mix?

[kohburn]

Originally Posted by SpudRider

CSC is employing the exact same logic we concluded on this forum, but is aiming for a different result. Placing the OCS in the CSC orientation maximizes the amount of fuel collected in the clear tube at the bottom of the OCS. Placing the OCS in the opposite orientation minimizes the amount of fuel collected in the OCS, and sends more atomized fuel to the air box, where it can be burned in the combustion process.

and emissions, ok yeah that makes sense that it would be done that way for emissions. on cars i've only ever used a catch can in the crank case vent line to avoid oil fowling of the intake sensors and spark plugs. never a concern about unburnt fuel vapor.

[SpudRider]

Originally Posted by AdventureDad

I dont have mine yet...but I'm wondering for those who take long rides, what happens when the tube gets totally filled and one keeps riding? I'm not saying ignore it, but if someone is doing a long ride out of state or whatever, and the tube gets filled and the rider misses it, what could a negative outcome be?

If the water/fuel mixture rises to the top of the OCS, the air box will be unable to draw the contaminated fumes from the crankcase. Therefore, the fuel and water will remain in the crankcase, contaminating and thinning the engine oil.

[SpudRider]

Originally Posted by detours

This has happened to me several times on rides longer than 3-4 hours. I've pulled the tube out from the OCS and liquid drips out of the OCS for a minute.

This means that fuel is starting to fill the OCS and block suction. When that happens, vapors will no longer be drawn from the crankcase and fuel will build up in your oil...

That is exactly correct.

Originally Posted by detours

...Obviously, you can drain it at every stop ... or pull the plug and let the fuel/oil/water drip to the ground all the time. But I really hate the idea of pouring out even more fuel than I already have to...

I would not pull the plug. The suction from the crankcase can draw dust, water vapor, and other contaminants into the crankcase, and/or plug the mesh screen within the OCS.

Originally Posted by detours

...Unless I hear a convincing argument (as to why it's better to pour gas on the ground than to burn it), I'm going to stick with the opposite orientation. I've been running it like this for several thousand miles with no ill effects, no loss of power and good mpg (65 to 70 mpg).

And if it makes the engine run slightly richer ... well, I was going to pour that gas out anyway. I might as well give it a chance to burn inside the engine before sending it out the tailpipe.

I'm with you. My RX3 was delivered with the OCS in the "unofficial" position. Since then I have ridden over 14,000 miles with my OCS in the "unofficial" position, and I have not noticed any ill effects whatsover. In addition, the OCS for my Honda XR650L is designed to burn the fuel vapors.



I can't see how it is preferable to spill the fuel, rather than burn it.

[SpudRider]

Originally Posted by detours

I have much to learn about emissions and fuel injection systems. But doesn't the O2 sensor detect O2 in the exhaust and optimize fuel injection to compensate?

In other words, if extra fuel vapor is added from the OCS, wouldn't the fuel injection system reduce fuel for an optimal mix?

Yes, you are correct if the O2 sensor is operating in a closed loop. I might be mistaken, but I believe our EFI systems don't operate in closed loop much of the time. However, I also have much to learn regarding EFI systems. Nevertheless, the O2 sensor should help to optimize the fuel/air mixture, as shown in the video below.

However, after watching the video, you will note that automotive systems employ two O2 sensors. One is located in front of the catalytic converter, and one is located behind the catalytic converter. While the first O2 sensor acts to optimize the fuel/air ratio, the second O2 sensor monitors the efficiency of the catalytic converter. Since our bikes lack the O2 sensor behind the catalytic converter, it is possible that exhaust emissions can be adversely affected by the extra fuel vapor introduced from the air box.

Nevertheless, it appears the RX3 bike submitted by CSC for EPA and CARB approval probably also had the OCS installed in the "unofficial" position, as it was with my own RX3. Therefore, I really don't see many adverse effects for burning the extra fuel, instead of spilling it on the ground.

[CSaddict]

I just flipped mine which is more difficult due to the aluminium skid. I'll flip it back.

[pyoungbl]

Every motorcycle EFI system I'm familiar with (Ducati, Triumph, Moto Guzzi) runs in closed loop up to about 3500 rpm and then switches to open loop for higher rpms. Ours might have a higher crossover point but I'm pretty sure the closed loop is only significant for us at idle or just above idle. The EPA cycle could possibly dictate testing at some highway speed as opposed to a specific rpm range so that in itself would modify where the ECU goes from closed to open loop. On the other bikes it is common to have drivability issues at low throttle settings unless the ECU is re-mapped or the owner installs a gadget like a Power Commander to modify the fuel delivery. We do not seem to have that problem and I see no need to mess with the fuel map.

The amount of fuel being dumped by the OCS is really pretty small. I'd guess less than a cc in the batch that I dumped. There is much more water. Personally, I'm happy to see any water vapor being pulled from the crankcase. If it goes to the airbox or the ground...either is a good thing just as long as it is not in the oil. One could always install a larger catch bottle if the volume is a concern.

[Juanro]

And what if one connected the crankcase directly to the air box?
Wouldn't it be then that all contaminants would be burned? And then forget about draining or collecting...