My bike experiences the same effects as detours bike does.
Standpipe is there for a reason.
When it's full you might have 2oz.of fuel...so what.
If the bike runs fine and maintains good gas mileage(60-65 mpg)
Then you need not worry.

Of course, you are entitled to your opinion, but I must disagree. The oil separator is not designed to capture combustible fuel. It is designed to capture contaminants from the oil, and to pass gas fumes to the air box. It is not good to leak combustible fuel into the environment, nor it is not safe to collect combustible fuel in a tube near the engine. ;)

As far as I know, no one else is having this problem. :shrug: If the oil separator is working properly for everyone else, except you and Detours, then I must assume you are having problems with the oil separator.

I strongly encourage you to examine the oil separator, and the hose leading to the air box. However, if you wish to collect fuel in the drain tube, it's not the worst thing in the world. ;) Nevertheless, the oil separator was definitely not designed to operate in this manner.

That is another way to look at it. ;)

:lol:

I believe that it is designed to capture some combustible fuel.You say it is a problem and I say it is not.I believe it does pass gas fumes to the air box for 99% of it but at high speed some fuel falls out of suspension and that is one of the jobs of the stand pipe...to collect it.That is my theory FWIW.
But I have enlisted the help of a guy who could probably clear this up,
Joe Berk of CSC.He rode 5,000 miles at 8,000 RPM's(also the name of his book he just wrote)With Zongshen engineers riding along with him and I'm thinking he may have some insightful info into this.
I have not seen him on this forum but he does frequent the ADV rider thumper section under our bike.
I went on there and posed the question to him so maybe we will get an answer beyond the speculation.

Thank you. It will be interesting to hear what Joe has to say regarding this topic. :)

Meanwhile I am going to run a test...I am going to eliminate the separator,clear standpipe and air box from the system and run the crankcase tube right where it comes out of the crankcase into a breathable catch bottle then go out for a high speed run of 10-20 miles and see what if anything is in the catch bottle.

If you have time, please examine the oil separator, and take a few photographs of it. Also, please examine the hose leading to the air box. I suggest you cover the area where the hose entered the air box. This area is behind the air filter, so any dust particles which might enter it will be ingested by the cylinder. ;)

I am having a hard time believing me and detours are the only 2 guys catching fuel in the clear tube.:hmm:
I wonder how many riders are watching for it because it will empty itself on its own.

I hope anyone else who is collecting fuel in the down tube will report it in this thread.

If you like the pic, check out the video :)

https://drive.google.com/file/d/1ZXR...ew?usp=sharing

Egads! :wtf: Is that the fuel you collected from your crankcase vent collector?

Yes, when we got back from our 4-hour ride yesterday, the catch tube was full. I dumped it all into this can and it burned like you see.

My goodness! It's not safe to be collecting that fuel near the engine. :ohno: Have you had a chance to examine the oil separator?

No, I can see how to disconnect it, but I'm not sure what to look for when I get it off.

I haven't had mine apart, so I don't know what to look for either. ;) I'm reluctant to take mine apart, since it is working so well. :hehe:

I would look for goop which creates obstructions, holes, obvious manufacturing defects, et cetera. The hose leading to the air box should not have any holes or kinks, et cetera.

I will probably pull mine apart in the next few days. ;)

Gatling (Joe from CSC) just posted on page 47 of the advrider forum on this topic, looks like it's normal for the bike.

http://advrider.com/index.php?thread...007040/page-47

Mine collects fuel at the same roughly the same rate as detours. I've since drilled a small whole in the bottom of the plug as a temporary solution. I think a lot of people don't notice because the plug can be a poor seal in the tube due to molding lines on the plug and the fuel slowly drains away. I cleaned mine up with some sand paper and that's when I would notice fuel accumulation. Also after and extended high speed run near red line and I stop there will be fuel driving from the line

I still believe it's fuel vapor from the engine crank case condensing out at the separator. But I want to separate the air box fro the crank vent and test to know for sure. I need to prove to my self that under some strange flow condition it's not coming from the fuel injector back down the crank vent tube. Unlikely but I've seen stranger things in my years of engine related stuff.

I'm also considering removing all of the separator stuff and just pluming strait to the air box like every other engine I've dealt with does.

3banger, you've made some very interesting comments. I'm aware that gasses from the combustion process leak past the rings and end up in the bottom end. I'm also aware that such pressure needs to be vented from the bottom end, or it will find a way out.

What hadn't occurred to me is that fuel in suspension could be condensed and collected. I now wonder how much fuel would be produced by any of the bikes I have. I always presumed there would just be pressure and a bit of oil; I never considered that fuel could be returned to a liquid state like that. This is fascinating to me.

That is not exactly what he said. ;) He said it's normal to collect oil, water, and contaminants in the down tube. He also said the liquid collected is not fuel. However, we know the fluid collected by Detours is very combustible. ;) Here is an exact quote.

"Although it smells a bit like gasoline, the Zongshen engineers tell us it is not fuel. It is a mix of oil and water (condensate) from the crankcase."

In effect, he said the Zongshen engineers told him the down tube is not designed to collect fuel.

I think your presumptions are still correct, Weld. ;) I don't believe it is normal for liquid fuel to be collected from the oil separator. I just made a telephone call to CSC, but Gerry, the maintenance supervisor, is not a work today. ;)

I need to sand the inside of the down tube to positively confirm I am not also collecting combustible fuel. ;)

The next time you collect some fluid, please do try to ignite it.

Indeed, you can eliminate the oil separator, and route the crankcase vent directly to the air box. However, all the contaminants being collected by the oil separator will then stay in the crankcase, diluting, and contaminating the engine oil. The used motor oil I collect is always in excellent condition, so I am very pleased with the design of the oil separator installed on the RX3. :tup: In addition to removing the contaminants from the engine oil, I also like to be able to inspect the nature of the contaminants being expelled from the crankcase. :)

If it is normal for the down tube to collect gasoline, that doesn't bother me. I am genuinely interested to know whether or not this is normal. ;) If it is normal, I'm glad the fuel is being removed from the crankcase, instead of remaining inside to dilute and contaminate the engine oil. :)

Sand the molding seams off of the plug so it will positively seal in the clear plastic tube. I also put a light coating of silicon (dielectric) great around the plug to insure a good seal.

I haven't tried to burn any of the fluid but it smells so strongly of gas that I have little doubt what it is. And as said right now I've drilled a small hole in the plug it simply drains away. Though I would like to find a better solution, not a huge fan of dripping gasoline on back roads or anywhere for that matter.

You realize through heat and pressure you can create kerosene/diesel then gasoline in the refinement process. If in fact the engineers are saying it's impossible for fuel to enter that line, but what is going into that line is combustable, then the engine oil is clearly being refined to a certain extent during regular driving.

I'll bet you can drain off that "fuel" and it's basically good enough to run a small R/C car motor.

So I changed my oil today and I'd swear that it's diluted by fuel.
I change all my bikes and cars and truck oil myself and I know oil vicosities and my oil came out like water.
Someone on this forum had a Fuel Injection dribble as I remember but how does it get into the crankcase ?and could this be related to the excessive fuel in the separator tube ? The plot thickens or thins in my case.
I wonder if Detours notices a very thin,almost watery oil when he drains his oil ?

I'm sorry to say I am not surprised. Katflap in the U.K. had fuel in his motor oil. :ohno: Something is not right with your engine. My used motor oil is always in excellent condition.

I will do that tomorrow. :)

Luckily, no. I changed my oil a couple of weeks ago at 2000 miles, which is after I noticed fuel collecting in that tube. The oil looked normal, definitely not any thinner than oil changes on other bikes or cars. Didn't smell like gasoline either. It was a little dark, but for my 2nd oil change, barely out of break-in, that seems normal.

I noticed Joe said it could happen if you overfill the oil. I'll recheck the level with the proper procedure, but I sincerely doubt that's the issue unless the 1.7L spec is wrong. I carefully measured 1.7L (not quarts) of refill oil after completely draining from the plug and all 3 filter holes. I know some oil remains, but not much if you drain it warm and tilt the bike both ways, so I really doubt that's it.

I am just assuming fuel is thinning my oil because what else would ?
It actually did not smell of fuel and it did not light.
If it is fuel in my crankcase I am at a loss as to how it could get there.
The only path that I'm aware of for fuel to get in the crankcase is by the piston rings but that isn't happening because I'm getting 60-65 mpg and my plug looks fine.

I'm only speculating, but if the pump has held pressure and the injector doesn't fully seal, allowing some gas to dribble by when the engine has been shut off, then it will flow down the inlet port past an open valve in to the cylinder. Flowing down the wall and through the gap in the rings will be how it gets in the crankcase.

Jay.

If you severely overfill the oil, the excess oil will definitely come out the crankcase vent, and collect in the down tube. However, overfilling the oil will not cause fuel to collect in the down tube.

The specification is 1.7 quarts, not liters. I fill my engine with 1.7 quarts, which is 1 quart, plus 22 ounces. This amount of oil fills the sight glass perfectly when you measure the oil level using the proper method.

That could possibly be what is going on.That is the best possible answer I have heard.I talked to Gerry at CSC and he said it was normal to see clear fuel/water/contaminants in the clear tube.He said he has been in discussion with the factory about it.I told him that you could light it but it could be diluted quite a bit and that still happen because of the vapors.
So I am ok with a fuel like substance collecting in the tube and chalk it up to a particular trait with this engine/injection high revving engine.But I am still perplexed by the thinning of my oil and so I will drain it in a few hundred miles again to see if it is still going on.The fella in England had a similar problem as me and went as far as to change the injector but it made no difference.
If there is a fuel dribble happening after engine shutoff maybe it is in the controller(ECU).Of course if it were bad enough you could risk a liquid lock condition.Checked my gas mileage this morning and I'm getting 65 mpg.It will be interesting to see what my oil looks like here after a few hundred miles.

You could send an oil sample to one of those testing labs for absolute confirmation of fuel in your oil.

Out of curiosity can you get a sample of your oil to flash over if you hold a flame to it?


/

I did try and light the oil but it would not.
It has to be fuel that is thinning it,if it were water or coolant I would see a milky substance.
I noticed that Joe at CSC has just posted on the blog explaining the venting issue as explained to him by the factory.

Thanks for informing us of Joe's post regarding this issue on the blog. :) Here is a link to his post.

http://californiascooterco.com/blog/?p=18289

After reading the explanation by the Zongshen engineer, I now understand what is happening. ;) When starting a cold engine, some fuel can stick to the cylinder wall, and seep into the crankcase mixing with the oil. Gasoline is much more volatile than motor oil. Therefore, after the engine warms up, the diluted gasoline exits the oil as gasoline fumes. These gas fumes are added to any contaminated gases which bypass the piston rings, and the combined gases exit the crankcase vent. Here is a quote from the Zongshen engineer.

"When the rider cool starts the engine or when the engine is started in a low temperature, ... some liquid gasoline may stick to the cylinder wall and goes into the crankcase ... When the temperature of the engine turns higher, the liquid gasoline are volatilized and mixed with air and turns into a mixture air material.

http://californiascooterco.com/blog/?p=18289

Wikipedia describes the purpose and function of crankcase ventilation as follows.

"During normal operation, a small amount of unburned fuel and exhaust gases escape around the piston rings and enter the crankcase, referred to as "blow-by". If these gases had no controlled escape mechanism, the gasketed joints would leak...also, if the gases remained in the crankcase and condensed, the oil would become diluted and chemically degraded over time, decreasing its ability to lubricate. Condensed water would also cause parts of the engine to rust. To counter this, a crankcase ventilation system exists. In all modern vehicles, this consists of a channel to expel the gases out of the crankcase, through an oil-separating baffle, to the PCV valve, into the intake manifold. In a non-turbo engine, the intake manifold is at a lower pressure than the crankcase, providing the suction to keep the ventilation system going."

https://en.wikipedia.org/wiki/Crankcase

As the contaminated gases enter the oil separator, the water vapor cools, and condenses into a liquid. Gasoline is much more volatile than water, but some of the gasoline fumes will also condense. The hotter gasoline fumes will pass through the oil separator, and be drawn into the air box. Once again, I quote the Zongshen engineer.

"But when this mixture material comes into the overflow line, it is cooled, and it becomes a mixture liquid material of gasoline and water. It is a condensation phenomenon."

http://californiascooterco.com/blog/?p=18289

The liquid collected in the down tube is a mixture of water, combustion contaminants, and some fuel; however, the fuel is greatly diluted. The system is designed so large amounts of raw gasoline cannot exit the crankcase ventilation system.

I've got to say I'm loving how they pay attention to the blog then follow up on questions, that's having the finger on the pulse of your customer base!

Good to know it's nothing serious, maybe its a feature, "camp fire starter tube"


Lee

I like that. :) When you get to camp, drain the down tube to help start your fire. ;)

The crankcase vent system of the Zongshen RX3 is very nicely designed. I think it superior to the crankcase vent system installed on my Honda XR650L. :)

In the Honda System, crankcase gases are vented to the air box, but crankcase contaminants are returned to the crankcase.

http://i729.photobucket.com/albums/w...r/oil_sep2.jpg

In the Zongshen system, crankcase contaminants are removed from the engine, and deposited in the down tube.

http://californiascooterco.com/blog/...1_4723-650.jpg

Along with the large oil capacity of 1.7 quarts, the elimination of crankcase contaminants keeps the engine oil in excellent condition. The used motor oil I drain from my Zongshen RX3 looks better than the used motor oil I drain from all my other motorcycles. :tup:

In addition, you just might get some combustible fluid from your 'campfire starter tube.'

:lol: