Overflow tube issue

[dpl096]

Originally Posted by JKR

Thx again guys. I talked to Gerry at CSC about the position of the OCS. Basically he says "cap" side up but in all honesty shouldn't make a difference. I've been paying more attention and the tube fills close to full after 40-50 miles. I'm toying around with the idea of doing the bypass thing but still have concerns about that much "contaminated" fluid making it to my air box or mucking up my oil in the engine or blowing nasties out the exhaust. I'm not sure if that's a valid concern or not as I am barely mechanical, have an idea, learn quick but you know...

JKR ... The stuff coming out of the crankcase is gaseous/vapor and by reintroducing it in that same state back into combustion it is burnt as intake gasses. Others have been doing this and their oil is "clean" and fuel-odor free at servicing rather than thin and having noticeable fuel odor content.....I've had no build up of fluid in my airbox drain line, which is capped just for that reason.

[detours]

Originally Posted by Azhule

The Bashan 200 and I are mentioned and pictured in that blog too

Yep, and Rojo_grande and his TT250

[detours]

Originally Posted by dpl096

JKR ... The stuff coming out of the crankcase is gaseous/vapor and by reintroducing it in that same state back into combustion it is burnt as intake gasses. Others have been doing this and their oil is "clean" and fuel-odor free at servicing rather than thin and having noticeable fuel odor content.....I've had no build up of fluid in my airbox drain line, which is capped just for that reason.

So far, I've had the same results as dpl096.

The way the OCS line is routed, it connects to the airbox below the air filter and points toward the rear of the airbox, in the opposite direction to airflow. Any vapors will be drawn up and into the air intake.

If they make it that far without dripping back down into the crankcase, any oily contaminants or fuel should hit the back wall or bottom of the airbox and eventually collect in the airbox catchtube.

My airbox catchtube has been clean so far, but when I clean my air filter this weekend, I'll inspect the airbox and look for oil residue on the surfaces.

[rjmorel]

I drilled a 1/16" hole in the black plug at the end of the drain tube so any liquid is constantly being drained out in very small quantities as I ride. Haven't looked much at it since. rj

[2LZ]

Originally Posted by rjmorel

I drilled a 1/16" hole in the black plug at the end of the drain tube so any liquid is constantly being drained out in very small quantities as I ride. Haven't looked much at it since. rj

Up until EPA regs, all my old bikes just vented to the ground.

[JKR]

Wow, great replies all. I will most likely give the direct line route a shot. I've been getting great advice from this site since I got Chang (bikes name) and is the first time I've posted a question. Awesome support, I just cant thank you all enough!

[jbfla]

Originally Posted by jbfla

.......

.....

An unexpected development on the OCS removal experiment.

I was wondering why the clear plastic tube has remained so clean.

It turns out that when the engine is hot, the plastic tubing is heated (softens), and collapses at the bend. When it cools, it opens up again.

I will replace the tubing today with some reinforced tubing.

jb

[JKR]

Found something interesting. In my original post I explained that the seal in the left crankcase cover was bad and oil was flowing into the overflow. It got to the point to where I noticed in the oil view window it had gone down significantly. After the seal was replaced the oil level has remained static. I have always wondered where that oil went, didn't seem as though the amount missing from the crank case was accounted for the amount draining from the overflow. This was a month and a half ago. After reading this thread I had seen mentioned some sort of view tube off the air box. I was trying to look in my air box to see if it had oil but really couldn't tell. Well... I found the view tube, removed it and 10oz of oily fuel smelling liquid drained from my air box. I will reiterate that my bike has been running great, no idle or dying issues. I am assuming that what was in my air box was the missing oil. Anyway, I rode my 20 miles into work today and still see the 2 inches of fluid in the overflow tube AND it looks like there is oily liquid in the air box view tube. I'm hoping its just residual fluid still in the air box and it will settle out as I ride and drain daily. Anyhoo, thats where I am at this point. I plan on riding and draining daily and if it does not improve I'll be contacting Gerry at CSC to see what his thoughts are on the matter. Thanks again for reading my long winded posts!!!

[rjmorel]

JKR, if you see liquid in the ocs drain tube then that means the system is working as it should and nothing to worry about I would think ????? It's removing the moisture and taking it out of the motor. rj

[JKR]

Right, it absolutely is doing its job. It's the amount of fluid that is a bit concerning as it completely fills up after 40-50 miles of regular riding. Also the other concern is how much fluid came out of my air box. I drained it thinking this fluid came from when i had the bad seal in the crank case cover replaced. But after my ride this morning I see fluid still coming out the air box. Hopefully its just residual from the previous issue but was hoping to see NO fluid from the air box after being drained.

[Azhule]

I would still slap a PCV on that crankcase vent/tube and be done with it... why the engine is fuel injected and they forgot a simple thing like 800 year old PCV technology is beyond me...

[JKR]

Please forgive my ignorance. What is the PCV option?

[detours]

The idea is to put a one-way check valve on the PCV line to the airbox.

As the piston moves up and down, it creates alternating positive and negative pressure in the crankcase. When the piston comes down, positive pressure helps push fuel and water vapor out of the crankcase. When it goes back up, negative pressure sucks some of that vapor back in.

This may explain the condensation we see in the OCS. On the low pressure cycle, the vapors cool off, condensing before it reaches the airbox and dripping into the catch tube.

A PCV check valve would only allow vapor to escape, hopefully preventing the low pressure and condensation. I need to find time to get to the auto parts store and look for a check valve that fits the line to the airbox.

[jbfla]

Originally Posted by detours

The idea is to put a one-way check valve on the PCV line to the airbox.....

Detours, Does the PCV valve rely of suction (negative pressure) from the airbox?

When I replaced the hose today from the crankcase to the airbox, I put my finger over the end of the hose with the engine running and could feel nothing.

Replaced the plastic hose with braided vinyl hose (1/2" ID)



jb

[jbfla]

Detours,

Nevermind, I re-read your post and all is clear!

Originally Posted by detours

...
As the piston moves up and down, it creates alternating positive and negative pressure in the crankcase. When the piston comes down, positive pressure helps push fuel and water vapor out of the crankcase. When it goes back up, negative pressure sucks some of that vapor back in....

jb