Fuel Economy

[SpudRider]

Originally Posted by RedHawk47

Spud,
You are going to drive me crazy. In both of the photos the OCS is in the same position. Also, I don't think the loop in the tube makes a difference as long as it is not pinched off. I don't remember what thread the earlier photos were in...

There was nothing in the "campfire tube" and nothing has ever leaked from it.

Because of the weather since I got it in October I have only run two tanks of gas through it. Mileage are 63.9 and 61.6 MPG.

So, is my OCS correct or upside down?

Originally Posted by Jay In Milpitas

It's not so much about the hose, Dan (a lot of Dan's here) as it is about the orientation of the workings inside the OCS.

So far I have only had juice in my tube twice, and there was no difference in how I operated the bike.



I keep reading that second statement and something just doesn't seem to sound right.

I'm not trying to drive you crazy, Dan. Your OCS is in the incorrect position. I am not primarily concerned with the loop being pinched. The tall pinch in the loop is merely an easily recognized indication that the OCS is in the wrong position.

Jay and Detours are correct. It is the internal construction of the OCS which matters, not the pinch in the tube. The pinch in the tube merely indicates the OCS has been positioned upside down, and will cause the OCS to deposit more gasoline in the collection tube, instead of allowing more gas fumes to be drawn into the air box, and added to the fuel/air mixture.

As Jay stated, proper orientation of the OCS might not noticeably increase fuel mileage. However, it will allow more gasoline fumes to be consumed by combustion, rather than condensing the fumes as liquid fuel in the collection tube.

As Detours has shown in the following photograph, the screen inside the OCS is shaped like a cup.

http://www.chinariders.net/showthrea...el+tube&page=6



The photograph aboves shows the OCS in the upside down, or incorrect orientation. In this position the gas vapors drawn from the crankcase only pass through the side of the screen, since the top is open. This increases the velocity of the fuel vapors as they are drawn toward the air box. As the velocity of a fluid increases, pressure decreases, according to Bernoulli's Principle.

https://en.wikipedia.org/wiki/Bernoulli%27s_principle

Bernoulli's Principle predicts the air traveling over the top of an airfoil must move at a faster speed than the air moving under the air foil. Therefore, the top of the airfoil has lower air pressure, which generates lift.

[SpudRider]

However, lower pressure also promotes the condensation of gases, as shown in the video below. Therefore, when the OCS is positioned upside down, the lower pressure increases the condensation of fuel vapor.

The video below shows the wing of a Boeing B737-400 taking off in the rain from Seattle-Tacoma airport. Just as the plane starts to lift off the ground condensation is observed over the top of the wing. This phenomenon is caused by low air pressure over the wing causing water vapor in the humid air to condense.

[SpudRider]

When the OCS is positioned properly, the cone of the screen is located at the top of the OCS. As the fuel vapors pass through the second screen, their velocity is decreased. The decrease in vapor velocity results in an increase in vapor pressure. This higher pressure helps the volatile fuel vapors to remain in a gaseous state. The less volatile water vapor condenses to a liquid, which is collected in the down tube. More of the volatile fuel vapors remain in a gaseous state, and are drawn into the air box, where they are consumed in the combustion process.

Detours has verified the collection of less fuel in the down tube after he flipped his OCS to the correct orientation.

http://www.chinariders.net/showthrea...el+tube&page=9

[RedHawk47]

Spud, Jay, Detours
Thanks for setting me straight.
Spud - what was making me crazy was that you had two photos with the OSC in the same direction and you said one of them was wrong.
It's all OK now.
Thanks

[SpudRider]

When the OCS is positioned as show below, the internal screen is in the correct position, with the cone of the screen at the top.



Since we can't see inside the OCS for the proper orientation of the screen, we use the external location of objects to verify the proper orientation.

The tube should be located at the top of the OCS. The clamp should be located at the bottom of the OCS.

[SpudRider]

When the OCS is positioned as shown below, the internal screen is in the incorrect position, with the cone of the screen at the bottom.



Since we can't see inside the OCS for the improper orientation of the screen, we use the external location of objects to verify the improper orientation.

The tube should be located at the top of the OCS. The clamp should be located at the bottom of the OCS. These objects are inverted in the photo, which shows the improper orientation. The big loop in the tube also indicates the internal screen is improperly oriented.

The tube has a big loop because it must travel to the bottom of the OCS. The problem is not caused by a pinch in the tube. The big loop in the tube is merely an external indication that the internal screen is upside down, which will promote the collection of more liquid fuel in the down tube.

[SpudRider]

Even if the OCS is upside down, you might not collect any fuel in the down tube. The fuel vapors are still condensing into the tube, but the tube might not be thoroughly sealed. If you shave/sand any imperfections in the plug, and seal the plug with grease, you will definitely collect a mixture of water and fuel in the down tube.

When the OCS is oriented properly, you will collect less condensed fuel in the down tube. This will better protect the environment, and reduce maintenance, since it allows you to empty the tube less frequently. It will also improve fuel mileage, but the improvement will be so small it will probably not be noticeable.

[SpudRider]

If you seal the plug so it collects liquid, you will notice more liquid in the tube with the OCS in the incorrect position. If you flip the OCS to the correct orientation, you will collect less liquid in the down tube.

The difference in liquid volume results from a decrease in condensed fuel. Instead, more fuel vapors are being conducted to the air box, where they will be added to the fuel/air mixture, and burned.

[SpudRider]

Originally Posted by RedHawk47

Spud, Jay, Detours
Thanks for setting me straight.
Spud - what was making me crazy was that you had two photos with the OSC in the same direction and you said one of them was wrong.
It's all OK now.
Thanks

You're welcome. I re-examined the photos, and you are correct. I made a mistake, and I'm sorry for causing the confusion. I have corrected the original post. The correct photos are also shown above in post #50, and post #51.

[Weldangrind]

Originally Posted by SpudRider

If you shave/sand any imperfections in the plug, and seal the plug with grease, you will definitely collect a mixture of water and fuel in the down tube.

Perhaps one might install a valve, rather than the plug. Pull up to the campsite, open the valve, harvest the campfire starter and start a fire.

[Lee R]

I did notice after riding yesterday that the little fluid that collected in the catch tube was a higher percentage water than fuel, it had a faint gas smell vs the strong smell previously. Looks like the separator is working properly now. I would expect some condensation to be removed as the humidity is over 80% here very often.

I don't think the fuel in the tube will make any significant impact on the MPG for the bike. That's more a result of a heavy guy who likes to wind up the bike often. Even when I'm gentle on the bike I still get 55mpg, it just takes more effort to get me up a hill

Merry Xmas everyone, hope your stocking were full of t-handles and other various goodies today!

Still in the 40's so it's time for a rare Christmas motorcycle ride.

[RedSpruce]

After reading this thread I went out to the cold(24 f) garage and checked my OCS. Mine was upside down! I have almost 2500 miles on the moto and my MPG with the stock gearing was always around 72.

I'll have to wait for a warm enough day to wash the moto and them flip the OCS over.

[Jay In Milpitas]

Originally Posted by RedSpruce

I'll have to wait for a warm enough day to wash the moto and them flip the OCS over.

That is one muddy machine.















I like it. Shows character.

[RedSpruce]

LOL, yes it stays fairly dirty except for the chain and the fork stanchions.

[SpudRider]

Originally Posted by Jay In Milpitas

That is one muddy machine.



I like it. Shows character.

X2; a dual sport bike doesn't look good until it gets dirty.