Oil Contaminant Separator (OCS) Orientation: The Official Word

[SpudRider]

Originally Posted by RX3James

I've been reading a lot about the orientation of the OCS lately. So today I decided to take a look at mine. As you can see it's not in the correct position. Only one time did I ever notice any fluid build up in the tube and it was when I was doing the break in oil change. It is pretty obvious with the discoloration of the tube that there has been fluid going through the tube for some time. I suspect its not building up in the tube because the plug isn't exactly water tight....

You are correct. My RX3 was delivered with the OCS in the same position as yours. I did not collect any fluid in the tube last year, because the seal was not tight. Over the winter the tube shrunk a bit, which tightened the seal with the plug. Therefore, I am now starting to collect fluid in the tube.

Originally Posted by RX3James

...So here's the real question..... I have not noticed any real issue with the bike. It runs and rides just fine. I think now that I've finally broken 2000 miles on it that I've worked out most of the bugs. So should I even worry about he orientation? Should I even spend the 5 minutes to flip it? What is it going to hurt if I just let it roll like it is? If there is no real benefit then I think I'm going to just leave it be. What do you guys and gals think?

Ride safe friends!

I have ridden my bike over 14,000 miles with the OCS in the 'unofficial' position. My bike also runs well, without any problems whatsoever. Indeed, at least some, if not all the bikes on the Western States ride also had the OCS oriented in the 'unofficial' position. Those bikes didn't have any problems, either.

Obviously, you don't have anything to worry about by keeping the OCS in the current, 'unofficial' orientation. Indeed, I would't waste five minutes to flip it, unless you want to experiment. If you do decide to flip the OCS, you will probably bend the tubing more acutely, which will probably cause the tubing to crack and fail more quickly. I can't see any benefit resulting from flipping the OCS to the 'official' position.

[SpudRider]

Originally Posted by RX3James

...So should I even worry about he orientation? Should I even spend the 5 minutes to flip it? What is it going to hurt if I just let it roll like it is? If there is no real benefit then I think I'm going to just leave it be. What do you guys and gals think?

Ride safe friends!

If you do decide to flip the OCS to the 'official' position for an experiment, you will collect more fluid in the OCS than now. Detours has proven this by valid experimentation. His results have also been confirmed by others who leave the OCS in the 'official' position for more than several days.

I have ridden my RX3 over 14,000 miles with my OCS in the 'unoffical' position. Every time I have changed my engine oil, the used oil was in excellent condition. Therefore, I'm sure I am collecting all the fuel and water contaminants from the engine oil. If you flip the OCS to the 'official' position, you will get more contaminants collected in the tube, which means less fuel vapor is being routed to the air box, and burned in the engine. Detours explains this matter in his usual intelligent, concise manner, in post #32 of this thread.

[3banger]

So here is the solution I will be testing out. Every other motorcycle I've ever owned or that I'm aware of vent from the crankcase directly to the air box with out all this OCS stuff. With a simple mod this can be accomplished on the RX3. I'm sure this will have warranty voiding implications if something I don't for see cause an engine related failure; Joe I realize that up front since I'm sharing this here.

As of right now this is an experiment and I don't encourage anyone else to following suit. But the engineer in me can't leave well enough alone; I'll keep everyone posted.

[detours]

Originally Posted by 3banger

So here is the solution I will be testing out. Every other motorcycle I've ever owned or that I'm aware of vent from the crankcase directly to the air box with out all this OCS stuff. With a simple mod this can be accomplished on the RX3. I'm sure this will have warranty voiding implications if something I don't for see cause an engine related failure; Joe I realize that up front since I'm sharing this here.

As of right now this is an experiment and I don't encourage anyone else to following suit. But the engineer in me can't leave well enough alone; I'll keep everyone posted.

What a great experiment! I see several potential advantages:

• Shorter line to the airbox could mean less condensation
• With no trap to fill, all vapor is burned in the intake. (None poured on the ground)

And some potential disadvantages:

• Heavy contaminants are not caught in the trap and stay in the crankcase.
• The straight shot will likely mean a faster stream of vapor. This creates a pressure drop, causing more liquid to condense than in a slower stream.
• Without a trap, condensation drops directly into the crankcase.

It's like a race ... Will the straight shot draw vapor into the airbox faster than it can condense and fall back into the crankcase?

As you test this setup, check the catch tube under the airbox after each run. I'll be very curious if liquid makes it to the airbox and is trapped there.

[Haggis]

Originally Posted by 3banger

So here is the solution I will be testing out. Every other motorcycle I've ever owned or that I'm aware of vent from the crankcase directly to the air box with out all this OCS stuff. With a simple mod this can be accomplished on the RX3. I'm sure this will have warranty voiding implications if something I don't for see cause an engine related failure; Joe I realize that up front since I'm sharing this here.

As of right now this is an experiment and I don't encourage anyone else to following suit. But the engineer in me can't leave well enough alone; I'll keep everyone posted.

That's exactly how GasGas run it, straight from crankcase to airbox.

[katflap]

In some performance car circles a separator is considered an enhancement, adding "catch cans" to their crankcase emissions system.

Apparently, oil vapour entering the combustion chamber can be detrimental to performance and fuel economy.

Zongshen didn't have to add this separator to pass emission standards, a straight forward tube will do that.

Blow-by gasses also contain acids that I guess wouldn't be good for the EFI sensors.

Perhaps these are the reasons its been added.

[SpudRider]

Originally Posted by katflap

In some performance car circles a separator is considered an enhancement, adding "catch cans" to their crankcase emissions system.

Apparently, oil vapour entering the combustion chamber can be detrimental to performance and fuel economy.

Zongshen didn't have to add this separator to pass emission standards, a straight forward tube will do that.

Blow-by gasses also contain acids that I guess wouldn't be good for the EFI sensors.

Perhaps these are the reasons its been added.

As always, you make excellent points, Kat. The Gas Gas bike in question has a carburetor.

However, I received my bike with an OCS in the "unofficial" position, and it ha been running very well for almost 15,000 miles, and averaging 68 mpg. Therefore, I don't see how keeping the OCS in the "unofficial" position can be detrimental to performance and economy.

I wonder how other motorcycles with EFI vent the crankcase gasses?

[dpl096]

I thought Joe's blog today was a fair and honest explanation of the mechanics of the issue and, for me at least, eases most of my concern of the 4 to 5% levels recently seen in the oil analysis. I'm still not certain it's a genuine constant across the board as everyone rides differently. I'm going to leave mine, when it arrives, in the correct orientation and will probably send a sample off to Blackstone at the 1000 mile mark for peace of mind - otherwise I'm gonna go with Joe's assurance and ride in peace. Might bump up to a heavier oil down the line but for the first 1000 I'll stick with the Mobil. What say the rest of you regarding Joe's blog ? ? ?

[pyoungbl]

Originally Posted by SpudRider

I wonder how other motorcycles with EFI vent the crankcase gasses?

Ducati, Triumph, Moto Guzzi, BMW...all vent to the airbox....at least all of mine did. EPA won't pass them if they vent to the atmosphere. Note that all of them are much larger displacement engines so the pumping action is more pronounced. Good venting is critical because otherwise you risk blowing oil seals in the engine.

[katflap]

Originally Posted by SpudRider

As always, you make excellent points, Kat. The Gas Gas bike in question has a carburetor.

However, I received my bike with an OCS in the "unofficial" position, and it ha been running very well for almost 15,000 miles, and averaging 68 mpg. Therefore, I don't see how keeping the OCS in the "unofficial" position can be detrimental to performance and economy.

I wonder how other motorcycles with EFI vent the crankcase gasses?

Sorry, how it meant to read was that having the OCS is a good thing as it will help to stop the oil vapour reaching the intake.

where a straight tube without the OCS will not and possibly have a detrimental effect on performance and economy.

As to the orientation of the OCS, i have no idea

[SpudRider]

Originally Posted by pyoungbl

Ducati, Triumph, Moto Guzzi, BMW...all vent to the airbox....at least all of mine did. EPA won't pass them if they vent to the atmosphere. Note that all of them are much larger displacement engines so the pumping action is more pronounced. Good venting is critical because otherwise you risk blowing oil seals in the engine.

Thank you for posting the good information, Peter.

I assumed all bikes with EFI vent to the air box. All of my street legal bikes vent to the air box. Many dirt bikes vent to the atmosphere, but they don't need to pass EPA or DOT requirements. I am wondering if your previous EFI motorcycles employed an OCS, or if they vented directly to the air box without an OCS?

[SpudRider]

Originally Posted by katflap

Sorry, how it meant to read was that having the OCS is a good thing as it will help to stop the oil vapour reaching the intake.

where a straight tube without the OCS will not and possibly have a detrimental effect on performance and economy.

As to the orientation of the OCS, i have no idea

I understand, Kat. I'm inclined to agree with you about the inclusion of the OCS. However, I wonder if other motorcycles with EFI also employ an OCS?

[katflap]

I guess there must be some out there

This image comes from a motor cycle technology book but the outline looks like a carb

[keithmaine]

The new fuel injected Urals go direct into the air box just like the carb version
as you can see below. The carb version does get a lot of oil and condensation in the air box

[2LZ]

Almost all of the early EFI's fired a load of fuel every stroke, whether the intake valve was open or not. That "blank" spray of fuel would sit on the back of the intake valve and vaporize/atomize while it waited. This process also increased the intake valve build-up due to the olefins and diolefins in the fuel. Ford (in American cars) brought out the first "SEFI" system that only fired when the intake valve opened.
I've heard that many EFI's today still work firing a charge every stroke. I wonder if the EFI on the RX3 fires in this fashion, with the injector firing every stroke? This may possibly increase the fuel in the oil (or drain tube). Does anyone know the actual injector firing sequence?
Just a thought......